Stuff You Should Know - What are false positives?

Episode Date: March 29, 2018

When getting a medical diagnosis, it's important to understand the terms. Negative is good, positive is bad, false positive is great in a way, but false negative is the worst. Learn all about false positives, when your tests indicate you have a disease of some kind when you don't, and what this means in the medical community at large. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

On the podcast, Hey Dude, the 90s called, David Lasher and Christine Taylor, stars of the cult classic show, Hey Dude, bring you back to the days of slip dresses and choker necklaces. We're gonna use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s.

We lived it, and now we're calling on all of our friends to come back and relive it. Listen to Hey Dude, the 90s called on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. Hey, I'm Lance Bass, host of the new iHeart podcast, Frosted Tips with Lance Bass. Do you ever think to yourself, what advice would Lance Bass

and my favorite boy bands give me in this situation? If you do, you've come to the right place because I'm here to help. And a different hot, sexy teen crush boy bander each week to guide you through life. Tell everybody, ya everybody, about my new podcast and make sure to listen so we'll never, ever have to say. Bye, bye, bye.

Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple Podcasts, or wherever you listen to podcasts. Welcome to Stuff You Should Know from HowStuffWorks.com. Hey, and welcome to the podcast. I'm Josh Clark, and there's Charles W. Chuck Bryant. It's just us.

There's no producer, there's no guest producer, there's no nothing. Just a ghost in the chair. Why is it whenever we're in this room, just the two of us, I go back to like elementary school or middle school and feel like we should just start drinking whiskey or something? Isn't that weird?

Yeah, well I guess Jerry kind of provides like a teacher-like presence. And I guess Noel is kind of like a substitute teacher-like presence, so. I didn't ever have the urge to drink whiskey in elementary school, but I can see where you're coming from. It was eighth grade before that started for me.

I didn't drink till college, but I don't know, it's just, and neither one of those Jerry or Noel would care, even. It's just some weird thing about the teacher leaving the room, after all these years, I'm still like, all right, I need to act up. Right, my thing went more toward paper airplanes than breaking out the pint bottle whiskey

I have in my sock. No. Again, I didn't even drink until college, so of course I wasn't doing that. I just probably started joking around. No, I know what you mean. But today's Chuck would hit the bottle. Right, actually today's Chuck is all business

because I hate to tell you this, buddy, but you're doing your job right now. That's true. We both are, because this is our job to podcast. It's funny, during the Emily and Chuck pre-Oscars mini crush show, it was kind of dragging on. She's like, this is starting to feel like a job. I was like, this is my job.

This is the job, the job. We talk about it like cops talk about their job, their job, we're real, real podcasters. The job. Remember that show, The Wire, have you ever heard of it? No, sure. No, I'm just kidding, we've talked about it before. But remember they called that one cop real police?

Yeah, real police. I can't remember a name. Yeah, they said that a lot on that show. Yeah, but they mostly talked about one officer in particular. That's real police. Trying to think of, yeah. Little real podcaster.

Right, there you go. I love it. So let's start real podcasting. Is this one gonna be a stinker? No, it's not, actually. It's actually really, do you know why? Because it has the hallmarks of a good episode. And I'm gonna peel the curtain back a little bit

for everybody, Chuck. Ooh, one of the hallmarks of a good episode, at least of stuff you should know, is that there is controversy associated with something, even where there doesn't seem to be. And that there are people who are either getting screwed over, suffering, being neglected, being abused. There is some group of people who the rest of the world

aren't really thinking of, who are suffering at the hands of other people. And this actually, this episode has all that, surprisingly. I'll let you guys guess where that stuff comes in. All right, so we're talking about false positives. And here's what that is. If you've ever been to the doctor, you've had a medical test done.

Generally, well, not generally. Always you will get one of four results. Yeah, good point. You can get a true positive. And remember, when you're getting a medical test back, positive is negative. Yeah, usually means bad news. Yeah, positive is not good.

They don't say, I have news. I have good news for you. Your results are positive. It's a little bit of a mind trick that you need to perform. But positive is you have this condition. Right, it means that the test that searches for a condition or a condition found a result. Yes, it is confirmed as yes.

Right, so that's what you should say. That's a true positive, right? Yeah, then you got a true negative, which means you don't have this. However, if you're like me or probably you and most people you say, that's good news, but I'd sure like to get a confirmation on that. Yeah, how do you know?

How do you know, doc? Then you can get a false positive, which is what we're talking about here. Right. Which is they say you have this condition, like let's say you have cancer. I'm sorry to tell you, but you don't as it turns out later on,

which is great, false positives are kind of, they should call it the new lease on life result. Right, the Dabney Coleman out of time result. And then the worst of all, probably is the false negative. Agreed, man, I'm glad you said that because this article just walks right past that fact. Yeah, that means results say you're fine,

but it turns out that you're not. Yeah, you're toast. So whatever the, and not even good avocado toast, you're bad burnt toast. Right, exactly. Terrible stuff with that really cheap sliced cheese that nobody would want to eat. What's the opposite of a lease on life result?

Early death, sudden early death out of the blue. Although there is something to be said about that, about just not knowing, right? Just out of nowhere, bam, you just fall over debt. That's not necessarily the worst way to go. Yeah, I guess I was thinking more on the play on words of, instead of a new lease on life, something to do with renting in your landlord.

So an old, we'll figure this one later and dub it in. Wait, what's it called when you get kicked out of your apartment? Oh, an old eviction of death. God. We did it, Chuck. Oh, man. So those are, if you take a test at the doctor,

those are the four possible results you can get. Correct. What's really interesting here, and this is something that you're going to want to remember. And after you hear the rest of what we have to say, you're really going to want to remember this. But when you hear something like this test that I'm about to give you is 99% accurate,

it doesn't mean that if it comes back with a positive result that says you have this thing, it doesn't mean there's a 99% chance that you have that. It just means that when they say a test is 99% accurate, that if you do have that disease, there's a 99% chance that this test will catch it. Okay? Huge, huge difference between those two things.

Okay? That's step one. So really what this is saying is that this test doesn't let very many false negatives get through. And if you look at the numbers, this is how that works out. If you have 10,000 people, Chuck. Okay.

And they take a test that's 99% accurate. And this is so 10,000 people and 99% of them don't have this. And it's a 99% accurate test. There's going to be 100 that come back positive out of 10,000. Okay? 99 of those positive results are going to be true. One is going to be a false negative.

Okay. Okay? 9900 are going to be negative. They're going to come back negative. 9800 and one are going to be true negatives. But 99 are going to actually be false positives, right? Okay. I know this is really mind-bending,

but if you take the numbers like this, that means that only one out of 9,802 people had a false negative. So that's a big deal. As you said, that's the big daddy. That's the one you got to really watch out for. But 99 out of 198 are false positives, which means that this 99% accurate test

has a 50% chance of giving you a false positive if you come back positive. Should I just not even have said any of that stuff? No, I think it's just funny that after 10 years, it's dawned on me that you have two true talents. One is explaining extremely complex things in a very easily digestible way. And the other is completely confusing me

with the words that come out of your mouth. Well, this is very confusing stuff. I mean, it's not just me. This is Bayesian statistics, basically. Yeah, well. The point of all of this is that first of all, if your 99% accurate test comes back that says you have something,

it doesn't mean you have a 99% chance that you have it. Yeah, very important. Number one, number two, if it does say you have it, there's a 50% chance that that test is wrong, even if it's a 99% accurate test, okay? That's a big thing to remember that if your doctor doesn't explain that to you, you punch him or her in the arm,

and you say, you're not doing your job fully because I'm scared, buddy. Yeah, I just got a positive test result and I'm scared out of my mind. So if your doctor's not gonna come for you, hopefully Bayesian statistics, well, and don't listen to me, go look it up yourself because I'm sure someone else on the internet

can explain it better than I can. Perhaps Mr. Billy Bayes. In his whole statistical model. Was he a character on Melrose Place? I think so, he's a pool cleaner. All right, so with medical testing period, like you said, if your doctor's not telling you that, with any tests that you take,

not all medical tests are created equally. Some are really accurate, some aren't as accurate as they, well, that's what I'd say, so they could be. They're as accurate as they can be, which is to say, maybe not as accurate as you would like it to be. Sure. But you really need to talk to your doctor

and hopefully they're offering this up anyway, like, hey, what's the deal with this test? How reliable is this? Do I need to get a second test? Because the whole thing with false positives and false negatives, and even true positives and negatives, is there's a bunch of different reasons why follow-up testing is both good and bad.

Like, sometimes these procedures, like the follow-up isn't like a pinprick, sometimes it's an actual surgical procedure that you may not need, a lot of times, and we'll get into these more specifically, but there's expense involved. A lot of times you didn't need to spend that money, but it's hard to say because you should be

your own medical advocate and spend whatever money you can to ensure that the testing is reliable. And then there are things like the time that it takes between these things, like, all right, we'll see you, we need to follow this up with another test, but it's gonna take three months to get you in, and in the meantime, in those three months,

you're stressing out, you're up all night, you can't sleep, your sex drive is out the window, that sounds like a silly thing to talk about, but it's a real thing. Especially when you're grown-ups like us. Yeah. It's important. But it's a, here's a study from 2009,

so granted this is a little old, but it's from the Annals of Family Medicine. And when it came to tests for prostate, lung, colorectal, and ovarian cancers, they found that positive, false positives after four tests, they did test, I think either four tests or 14 tests. After four tests, you had about a 37% chance for men

and a 26% chance for women for false positive. And then the more tests you got, the more that went up, which is distressing. It is, something like if you had 14 tests, all 14 of the tests that they studied, you had a 60.4% chance for men and 48.8% chance for women of coming back with a false positive.

And again, this isn't just like it's, yes, you have that new lease on life on the other side, but studies have shown like these, getting a false positive result from a test, it can be emotionally devastating and it can have an impact on your finances if you're a Scrooge McDuck type who's only moved by the idea of money.

Well, and your physical health because of stress. Yeah, because it's not like you're not addicted to man-witch in the time, just because you're stress-eating the whole time. So that's not good for you. What was man-witch? Man-witch, it was a canned sloppy joe starter. Okay, I know it's a meal.

And well, it's more than a meal. A sandwich is a sandwich, but a man-witch is a meal. Oh, that's right. I got it wrong. And you're like, no, it's more than a meal even. Right, it's even greater than the ads per prophecy. So the financial costs, like you were talking about Scrooge McDuck,

40, they did another study of about 1,000 people. And this was in December of 2004 in the issue of cancer epidemiology, biomarkers and prevention. That is a legit journal, just by the title. Oh, for sure. Oh, wait, and then it says Ann and wakeboarding, I tell you.

More than 40% of participants had at least one false positive. 83% of these people went on to receive additional care at a cost of about $1,000 for women and about 1,100 for men. So that's not a jump change. No, it's not. And a lot of people say, well, who cares? I got insurance.

Well, the healthcare spending is kind of a problem in this country. There's apparently in 2005, the National Academy of Sciences, big shout out to them. They found that there was 30% of healthcare spending was wasteful in the United States. 30% in 2005. And the idea of that gave rise to something,

there's a campaign called Choosing Wisely. Have you heard of that? No. So it's a campaign called Choosing Wisely. They have a site called ChoosingWisely.org. It's a joint effort between the American Board of Internal Medicine. So it's physician-based and consumer reports.

And they're basically saying like, there are a lot of unnecessary tests being performed out there that are leading to these unnecessary surgeries, unnecessary expenses, unnecessary anxiety. And we wanna figure out what they are and we wanna start advising people against them or at least advising doctors

to advise their patients against them because they might be unnecessary. And so this campaign has really kind of had a big impact as we'll talk about in a little bit. You know, the idea of breast cancer screening has changed, the recommendations have changed from what I understand from this Choosing Wisely campaign has really kind of just shifted things from,

well, this overabundance of caution can't be harmful to actually there are some harms involved in an overabundance of caution. Let's kind of streamline our caution and make it a little more laser focused. Should we take a break? Yeah. All right, we'll take a break and I'll hit you

with a stat right out of the gate when we come back. Boom. Let's go. Living things with junk and junk. Shocking all the things that you should know. On the podcast, Paydude the 90s called David Lasher and Christine Taylor, stars of the cult classic show, Hey, Dude,

bring you back to the days of slip dresses and choker necklaces. We're gonna use Hey, Dude as our jumping off point but we are going to unpack dive back into the decade of the 90s. We lived it and now we're calling on all of our friends to come back and relive it. It's a podcast packed with interviews, co-stars, friends, and non-stop references to the best decade ever. Do you remember going to Blockbuster? Do you remember Nintendo 64? Do you remember getting frosted tips? Was that a cereal? No, it was hair. Do you

remember AOL Instant Messenger and the dial-up sound like poltergeist? So leave a code on your best friend's beeper because you'll want to be there when the nostalgia starts flowing. Each episode will rival the feeling of taking out the cartridge from your Game Boy, blowing on it and popping it back in as we take you back to the 90s. Listen to, hey dude, the 90s called on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. Hey, I'm Lance Bass, host of the new iHeart podcast Frosted Tips with Lance Bass. The hardest thing can be knowing who to turn to when questions arise or times get tough or you're at the end of the road. Ah, okay, I see what you're doing. Do you ever think to yourself, what advice would Lance Bass and my favorite boy bands

give me in this situation? If you do, you've come to the right place because I'm here to help. This, I promise you. Oh god. Seriously, I swear. And you won't have to send an SOS because I'll be there for you. Oh man. And so my husband, Michael. Um, hey, that's me. Yep, we know that, Michael, and a different hot, sexy teen crush boy band are each week to guide you through life step by step. Oh, not another one. Kids, relationships, life in general can get messy. You may be thinking, this is the story of my life. Just stop now. If so, tell everybody, yeah, everybody about my new podcast and make sure to listen so we'll never ever have to say bye, bye, bye, bye. Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple Podcasts,

or wherever you listen to podcasts. All right. So before break, you were talking about breast cancer and mammograms in particular. And there was a study a few years ago in 2015, 2015, 2015, 2015. Yeah. About false positive mammograms and breast cancer over diagnosis alone at $4 billion a year. Billion. So it's just such a fine line of striking the right note with preventative care and over diagnoses. Yeah. And here's the problem. Like the tests, it's not like they're not out there saving people's lives. Yeah. It's not like the people like Dr. Papa Nicolau who came up with the pap smear said, oh man, this is going to be like a cash register for Western medicine. Right. That's not what these tests are designed for. Unfortunately,

they are used in some circumstances like that. In probably more circumstances than that, they're used again out of an overabundance of caution because no doctor wants to be responsible for missing something in their patient and leading to their patient dying. So they're using this overabundance of caution. The problem is that the tests aren't 100% infallible. They do have accuracy problems and some tests are better than others or another way to put it, some tests are worse than others as far as false positives go and take the pap smear in particular. With the pap smear, it looks for precancerous cervical cells. Three million women in the United States get a positive pap smear result from what I understand every year.

Only 3,000 of them have a deadly cervical cancer and that 40% of women will get a false pap smear in their lifetime. But here's the thing, 4,000 women who die in the U.S. every year from cervical cancer, most of them did not have a pap smear or hadn't gotten a pap smear in the last five years. So there's a tough relationship between using the tests and overusing the tests. And for every, say, I think 2,000 women who undergo a mammogram, one woman's life is saved. Well, those 2,000 women, they didn't know whether it was going to be, whether they were going to be the one whose life was saved or not. So to them or to their doctor, it was worth it. Unfortunately, 200 of them will get false positives and 10 of them will undergo unnecessary

surgeries, painful and necessary surgeries to remove non-cancerous suspicious cells in their breasts. So there's this idea where, yes, we need to use these tests. And then there's also this idea where we need to use these tests better or come up with more accurate tests. Yeah. I mean, in particular, mammograms and screening for colorectal cancer are two of the big ones that can show a lot of false positives. And they're sort of under the microscope as to how we can correct this. Moving forward, for instance, mammograms correctly identifies breast cancer 84% of the time. However, if you're younger, if you're a younger woman or if you have very dense breasts, you're more likely to have a false positive. And so because of this, over the past

like even 10 to 15 years, they've changed the recommended age a few times for when you should start getting these mammograms. It's gone from, I think in 2009, they recommended between 50 and 74. Then I think it went down between, I think it went all the way down to 40 at one point. 40 was where it started, I think. Oh, where it started, then up to 50. And now, I think this is the latest, as of a few years ago, the AC American Cancer Society said, if you are at average risk, and this is probably how they should do it, and not just a sweeping age, but if you're at average risk, you should start at 45 annually. But you could begin as early as 40. And I would guess that means if it runs in your family. And then after 55 every other year,

like Emily's mom and my mom both went through breast cancer. So Emily started getting mammograms. I think it, maybe even at 40, because she was in the higher risk group. Right, smart. Yeah, and they're no fun to go through. But she is, I think Emily has a good head on her shoulders as far as advocating for herself, but also not going off the deep end. Yeah, that's Emily like through and through. Yeah. Like she's not just going to sit there and be like, oh, whatever you say, doctor. And she's like, that actually doesn't sound quite right. She'll stand up for herself. Yeah, for sure. Yeah, advocating for herself. It's important. It is. So with mammograms, Chuck, from what I've seen, nobody's saying, well, this is a kind of x-ray. So you don't want to build

up the radiation. That doesn't seem to be the problem with overuse of mammograms. What seems to be the problem is that they, well, a mammogram is an x-ray and the x-ray is handed off to a radiologist and they apparently are like 84, some high 80% effective at finding cancerous tumors in breasts. Yeah, 84. Just looking at an image of a breast. This trained human being can say, yep, there you go, right there. Circle it, initial it, go follow this up. The follow-up is it results in a biopsy, usually a needle prick biopsy to remove some of the cells. Those are examined. And if those come back as suspicious, a doctor might say, we need to get those cells out. Most of the time, those aren't actually cancerous cells, but they're still

still being removed surgically, which is painful, costly and can be a problem emotionally to have to go through that surgical procedure to have cells removed that you didn't need to have removed. That's the problem with mammograms as far as getting them frequently. And supposedly between ages 40 and 50, a woman has a 50 to 60% chance of getting a false positive result from a mammogram. Yeah, man. I mean, a 60% chance. Yeah. And again, no one's saying, oh, don't get mammograms. They're going to just totally screw you up. It's more like medical community. We need a better way to find, to keep an eye on breast cancer. I mean, they're trying. Of sure they are. Of course they are.

And colorectal cancer is a perfect example. It is the second leading cancer-related death in the U.S. right now. Was it say here, 132,700 new diagnoses in 2015. And one of the big problems with colorectal cancer is that not a lot of, well, I'm saying a lot of people, but I think about 50% of people don't follow up on a recommendation to get a colonoscopy. Yeah. Because they don't want to get a colonoscopy. Yeah. So that's a problem. Have you got one of those? Not yet. Yeah, not having either. I'm really, really not looking forward to it. And I was researching it today and just almost fainted like three or four times while I was reading

the procedure about the procedure. Yeah. It's hardcore, man. There's like a finger-width tube that they stick in your anus, past your rectum, up to your colon, the cesium, I think it is, which is the top of your colon, which is basically where your rib cage ends on your left side. That's your cesium. So they go all the way up there and it has like a camera and a light on the end. And basically what they're doing is visually inspecting the inside of your colon. If they see something that they find suspicious, they can put forceps through the tube and take a sample of it and then just, you know, come on back out. Normally they'll give you a sedative for this. They also give you, I can't remember the name of the drugs, but it basically makes

you forget that it ever happened, like you prevent you from forming memories during the procedure. But most people don't want to go through this, even though it's extremely effective. It finds like 92% of colorectal cancer from what I understand. Yeah, it's amazing. With like all the advances of medical science, they're literally saying like the best way is to really just get on up in there and take a look. Just jam it up there, you know, get up there. However, they do have some, because like we said, about 50% of people won't even get a colonoscopy when recommended. They have other tests now. They aren't as accurate, but at least they're at least they're trying to get another test on the table for people that are reticent to have

the tube stuck up their butt. Right. And some of them work. There's this one called Colagard. From Germany. Yeah. They have an accuracy rate of 92%. No, no, no. This one is... Oh, well, yeah, yeah, yeah. Colagard was 92%. That's high, because I'm sorry. I misspoke earlier. The colonoscopy catches 94%. So this stuff that you just poop into a cup and mail it in and some porschmo tests it, right? That's 92%. That's really great. Well, it's not quite. It showed 92% of the cancers that a colonoscopy would uncover. Okay. So that's not 92% overall. Oh, okay. I got you. But it's still pretty good. Right. But it has a high, high false positive rate of 13%, which I mean, if you think a tube up your butt will make your

rectum pucker, so will a false positive of colorectal cancer. Yeah. The German one, although that might be German too, but there's another German... Actually, this is a German study about stool tests. And that's when you literally are just looking at trace amounts of blood in the stool. Well, some do. That had accuracy all over the place. That was from 25 to 72%, which I mean, that's such a wild swing that I don't know if I would opt for that. One of them, so one of them, some of them I should say probably most look for blood in the stool. Some look for DNA or genetic material of cancer in your stool. And then another one looks for chemical changes of a certain gene that could be present in your stool. And by stool,

of course, we mean poop by the way, everybody. And they analyze them for this. And again, they're pretty good at catching the stuff, but they're also pretty good at giving false positives. So, I mean, that's just a great... The idea that we can catch like 94% of colorectal cancers with colonoscopy, but 50% of people who need one don't go get it because it's such an awful procedure that like you were saying at the outset, like that begs for something new. Yeah. You want to take another break? Yeah, let's go prepare the finger width tubes. We'll talk about drug testing right for this. Okay. Okay.

On the podcast, Hey Dude, the 90s called David Lasher and Christine Taylor, stars of the cult classic show, Hey Dude, bring you back to the days of slip dresses and choker necklaces. We're going to use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s. We lived it. And now we're calling on all of our friends to come back and relive it. It's a podcast packed with interviews, co-stars, friends, and nonstop references to the best decade ever. Do you remember going to Blockbuster? Do you remember Nintendo 64? Do you remember getting frosted tips? Was that a cereal? No, it was hair. Do you remember AOL instant messenger and the dial-up sound like poltergeist?

So leave a code on your best friend's beeper because you'll want to be there when the nostalgia starts flowing. Each episode will rival the feeling of taking out the cartridge from your Game Boy, blowing on it and popping it back in as we take you back to the 90s. Listen to Hey Dude, the 90s called on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. SOS because I'll be there for you. Oh man. And so will my husband, Michael. Um, hey, that's me. Yep, we know that, Michael. And a different hot, sexy teen crush boy bander each week to guide you through life step by step. Oh, not another one.

Kids, relationships, life in general can get messy. You may be thinking, this is the story of my life. Oh, just stop now. If so, tell everybody, everybody about my new podcast and make sure to listen so we'll never, ever have to say bye-bye-bye. Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple Podcasts, or wherever you listen to podcasts. All right. So we've honed in on mostly medical testing up into this point. But, uh, if anyone's ever taken a drug test, there is always the risk of a weird false positive. You can be a clean liver and still get a test that said, hey, it says here that you smoked marijuana. And you can be like, dude, I don't and have never smoked marijuana. And then you have to plead,

like basically every athlete ever this test of positive or anything says, well, I didn't do it, man. It's a false positive. They're like, whatever, stoner. But it does. That's like, uh, the same thing with, uh, my Twitter account was hacked. It's like, really? Every time something awful came out on your Twitter feed, someone hacked it. Yeah. But Twitter hacking does happen and true false positives and drug tests definitely happen. Yeah, it depends on, on what you've been doing. Like, uh, if you are using a prescription medicine or even some over the counter medicines, you can come up with the false positive on a drug test. Yeah, it says between seven and 15 million people a year in the United States get a false positive drug test. That's a lot. Because think

about it when, you know, if you're applying for a job and you go do the drug tests and you go home and you hear that you got passed over for the job, I don't know if they tell you that it was because you failed your drug tests. And even if they do, they're not going to be like, well, we want to hear your side of the story. Mr. Candidate number 927. Yeah. You know, they, they, like you just, you just lost out on a job because of a false positive. You lost out on a sports scholarship. You lost out on, um, I don't know, uh, getting to deliver meals on wheels. Who knows, but you're going to miss out on something because of a failed drug test. When you didn't do anything, you've been a straight arrow your whole life. But again, you did, you made the mistake of

not keeping up with what prescription medicines can give you false positives. Yeah. And here's the thing, parents, if you drug test your kids, I'm not weighing in on that one way or the other, but if you drug test your kids and they return a positive test from marijuana and they say, mom, that's because I was in the car with some people who were getting stoned. That's how it showed up. Uh, it's not true. I hate to break it to you, but that is not, you will not, I don't think you can ever get a false positive for marijuana from secondhand smoke. Right. That's not your cue to burst into tears and grab Todd and go, oh, Todd, I knew you would never use drugs. And Todd's winking at the camera and breaks the fourth wall and winks at the camera,

Ferris Bueller style. Yeah. Todd stoked. It did kind of remind me though, because it said here that cocaine is one of the drugs that routinely do not come back with a false positive or a false negative. Yeah. It's kind of on the money. That means they have a good test for it. Well, yeah, but I kind of, that made me remember that old thing I used to hear that like whatever percentage of dollar bills has cocaine on it. And I thought that's totally not true. And one of those things that you just hear in school, but I looked it up and apparently that is totally true. That was a study just a few years ago in New York City by NYU and they found that 80% of dollar bills had trace amounts of cocaine. Yeah. Some ridiculous amount of euros do too.

Yeah. And not just cocaine. It's like there was some morphine, heroin and meth and lower quantities and then all manner of disgusting gross things on paper money. Right. Which apparently people were using to roll into a tube and sticking into their nose to ingest drugs with. Not word, but kind of always have. So the idea that you can find drugs on money, have you heard that there are like local laws around the country in the United States that say that police can confiscate money as drug money if they test it and it turns out that there's drug residue on it? Well, but it sounds like it's 80% of money. Yeah. Wow. Yeah. Not too cool. What are some of the other things that can give you a false positive? Aside from just jamming

dollar bills in your nose. Yeah. So remember that Seinfeld where I think Elaine was supposed to go on a J. Peterman trip, but she got disinvited because she turned up positive for heroin. Yeah. But it turns out that she was eating lemon poppy seed muffins every day. That apparently is true, although this article or how stuff works article gets it wrong. So the poppy seeds don't actually contain opium, but when you're harvesting the seeds, opium can rub off onto the seeds and depending. From people that were doing opium? No, no, no. So like they're harvesting opium from the poppy and then they're harvesting seeds later and then the seeds can come in contact with opium residue from the poppy plant and then however well they're processed or not processed,

by the time you eat them, they might have a substantial amount of opium on the outside of the shell, which will show up in a drug test. Crazy. Seinfeld was correct. Seinfeld was correct. Apparently ibuprofen can come back with a positive for marijuana, barbiturates or benes. Benes. And that was Jack Kerouac's drug of choice. Well, one of several. Yeah. Is that fair to say? But he really, I mean, I remember him writing about the benes a lot. Yeah. That's how we wrote that book in like 48 hours. Didn't he write that on like one long scrolling piece of paper? That's what I've always heard, but last time I heard that I was like 20 years old, so I never looked into it since. I think it's true. Well, I think I've seen it.

Jack Kerouac, let us know. Some OTC, cold and allergy medications apparently, can result in positive tests for like amphetamines. It's crazy. Yeah. Well, you know that like, like if you're making bathtub crank, you can use Sudafed as like a precursor or an ingredient in just crank. And that's why you're only allowed to buy like one box at a time with a driver's license. It's just 70s. Well, yeah, if you're using over the counter Sudafed to make your meth, that's crank. Yeah, it's crank. And then tonic water, surprisingly, apparently quinine contains a little bit of the real quinine, which is a drug. So here's the thing. I looked into this. I could not figure out why quinine would result in a positive test for heroin. Here's why,

Chuck. You ready for this? I'm ready because you know, gin and tonics are my jam. Okay. Well, just be careful because gin or tonic water does contain sometimes like 83 milligrams of quinine in it, which was a malaria drug, right? Well, back in the 30s, supposedly heroin dealers started adding quinine to their heroin to combat malaria. That was the urban legend. It turns out that's not the case at all. But quinine actually interacts with heroin in a way that kind of boosts it. And it also more to the point mimics heroin's bitter taste. So somebody would taste the heroin and what they were tasting was quinine, but they thought they had like some dynamite skag on their hands. So it was really just kind of to take terrible junk and make it seem like

it was much better by adding quinine. Apparently, this has been going on for so many years that drug tests test for quinine because they consider that an indicator of the presence of heroin. I think my big takeaway is here. Is it quinine and not quinine? I've heard both. Oh, okay. That's your big takeaway? Uh-huh. I was laying down gold. Well, here's my deal is lately, I've been buying the real deal tonics. Yeah, like fever tree? I hate to use the word artisan tonics. You should. But I've been buying the artisan tonics because they're delicious and I've really embraced bitter as a taste that I can enjoy

now here in my late 40s. I've never liked bitter at all, but I've kind of come around to it a little bit. Yeah, it is like the definition of an acquired taste, isn't it? Yeah, but now I really like it. And you know, these tonics that they make are like, they're made from the real, what's the root? The chinchilla. What is it? Chinchilla. It's not chinchilla. Chinchona. Is it chinchona? I believe so. Yeah, and that's like the key ingredient, right? Yeah. From what I understand, it is the key ingredient in tonic bar. I'm not an artisan tonic maker. Yeah, chinchona bark. So, I don't know if that's the key ingredient or if that's one of them. There's also like in white willow or something in that. Like an ingredient in aspirin is also in tonic water.

Yeah, I don't know. I enjoy it though. And it's the thing is, you don't use a ton of it. You just use like an ounce and then some club soda or whatever you may have artisan soda water. Oh, I see what you're saying. So, you're using artisan tonic, not with any kind of fizz. You're using like the tonic tonic. Yes. Oh, wow, man. That is, that's hardcore. It's like dark brown. I got you. And then you pour that in. It's like a couple ounces of gin, an ounce of that, and then top it off with some soda water, give it a good shake. Man, that sounds great. It's really good. And it has a nice... Can I come over today? Sure, come on over. I've started gin and tonic season early this year. That's great. Which is not good. No, it's great is what it is.

Oh, okay. Yeah, it's not good. It's great. Artisan tonic made from doomed goats. They have some... They have one kind downstairs at the 1821. Yeah, the Bitter's Place? Yeah, and I like theirs okay, but then there's another one in Avondale Estates that I think I like theirs a little more. So, is there like a specific tonic or just like the general tonic that they have? Well, the one in Avondale Estates is one called Dry Tonic and one called Robust Tonic. And I think the robust just has a little more lime citrus, but they're both delicious. I gotta try this stuff. Man, nice work, Chuck. I'm trying. Yeah, steer clear of the drug tests. I'm pretty sure they're going to start instituting them at Stuff Media any day now.

You know, the only drug test I ever had to take my entire life was when I went through the adoption process. Oh, yeah, I remember that. Never had to take one for work or anything? Nor have I. I think we're in the minority. You never had to drive a bobcat for work? I did, but the guy I worked for couldn't have cared less. He was insured to the teeth. Before we go, Chuck, you got anything else? I got nothing else. All right, so before we go, I found one test that is just supposed to be... It just seems to me like it's the gold standard for tests. It's an HIV screen, and it's called the enzyme-linked immunosorbent assay or ELISA. I think we talked about it in our HIV 2-parter. Yeah. This is how this test is performed.

So you get this one screen, the ELISA screen. If it comes back positive, a second ELISA screen is performed. If that's positive, a separate test that uses an entirely different technique is performed. All this is in the lab before you ever hear your results, and that means that one, in the United States, one out of 250,000 tests show a false positive. Whoa. That means that has a .000004% chance of returning a false positive. That's right. That is a bomb test. Yeah. Yeah. That's all I got. I got nothing else. Go check out choosing wisely.org. It seems pretty interesting to me. In the meantime, how about some listener mail? Yeah. I'm going to call this email from Mr. Swedman's class. All right. This is actually from Mr. Swedman and not his class, but we're

going to shout out his class in hopes that he starts incorporating this into his class. Hey, guys. Love the show on walruses. Wanted to chime in regarding reproductive isolation or reasons why different species don't mate. I have taught biology for several years, and evolutionary biology is always my favorite unit. Remember when we talked about reproductive isolation and what other different types of, like how that would manifest itself? I remember. So he says there are several types of reproductive isolation, and geographic isolation is one of them. And here's a little breakdown. Geographic isolation, when species live in different geographic regions, ecological isolation, same region, different habitat.

Okay. Okay. So they're in the same big city. They just don't hang out at the same clubs. Different neighborhoods. Different neighborhoods. Gotcha. Behavioral. I always have a trouble with that word. Isolation. One species mating behavior won't work on another. For instance, a peacock won't attract a chicken. Right. Because the peacock can't do kaka-cha, kaka-cha. No. What does the peacock say? Help. That's right. Temporal isolation, same area, but breed at different times. And that could be everything from the season to literally the time of day. That's called two ships passing in the night reproductive isolation. And that's like, I don't like morning sex. And the other one's like, shut up. I only like to have sex at night when

I'm drunk. Then there's gametic isolation. Mating can occur, but sperm and egg won't mix. No, not you again. And he says, in this case, it's usually the egg releases a toxin that kills the sperm. Quinine. That's right. And finally, he said, my student's favorite type of reproductive isolation. Mechanical isolation. Sure. That's when the parts don't fit. No. It's like, just wait, just hold on. Just give me a second. Wait, I can do this. And then nothing. He says, think square peg round hole. Sure. That's a really good way to put it. Way better than what I was saying. So there you have it, guys. All the types of reproductive isolation. Now you know, and knowing is half the battle. G.I. Joe. Nice job. Don't stop believing or whatever journey lyric guides your

life. That is from Mr. Baird Swedman. Thank you, Mr. Swedman. I love that you edited it. C.H. What is it? Swedman? It's just Swedman, but I like Mr. Swedman. Yeah, I have to call him Swedman. You know, Mr. Swedman from PS122. Right, exactly. That's how I'm doing it. Well, thank you very much, Mr. Swedman. I'm sorry I got it wrong the first time, but Chuck said behavioral wrong. So we're even. I could never say that right. If you want to get in touch with us, especially if you are one of the fine teachers instructing America's youth or any youth of any country around the world, because we think everybody's great. You can tweet to us. We're at SYSK Podcast. I'm at Josh O'Clarke. Chuck's at facebook.com slash Charles W. Chuck Bryant. He's also on

Twitter at Movie Crush. You can send us all an email to stuffpodcast at howstuffworks.com. And as always, join us at our home on the web, stuffyshinoe.com. For more on this and thousands of other topics, visit howstuffworks.com. We're going to use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s. We lived it, and now we're calling on all of our friends to come back and relive it. Listen to Hey Dude, the 90s called on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. Hey, I'm Lance Bass, host of the new iHeart podcast, Frosted Tips with Lance Bass. Do you ever think to yourself, what advice would Lance Bass and my favorite boy bands give

me in this situation? If you do, you've come to the right place because I'm here to help. And a different hot sexy teen crush boy bander each week to guide you through life. Tell everybody, ya everybody, about my new podcast and make sure to listen so we'll never, ever have to say bye, bye, bye. Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple Podcasts, or wherever you listen to podcasts.