Just How Little Does Government Trust Individuals?
From CNN via Carpe Diem
A 24-year scandal was quietly acknowledged last week. On July 3 the U.S. Food and Drug Administration approved the first "rapid home" test for HIV—a test that people can take in the privacy of their own homes to determine whether they have the virus that causes AIDS.
The approval is an unambiguously good thing—or so you would think. The saliva test in question, made by OraSure Technologies and known as OraQuick, costs less than $60 and takes just 20 minutes to self-administer. According to statistics an FDA advisory committee presented at a hearing in May, it holds the potential to prevent the transmission of more than 4,000 new HIV infections in its first year of use alone. That would be about 8 percent of the roughly 50,000 new infections we currently see annually in the United States. (About 1.2 million people in the U.S. are now living with HIV, according to the Centers for Disease Control and Prevention, of whom about 20 percent don't realize they have it. Since the epidemic began in the early 1980s, about 1.1 million people have been diagnosed with AIDS, and more than 619,000 have died from it.)
The scandal is that the approval of a rapid home test for HIV did not occur until last week—about 24 years after the FDA received its first application seeking permission to market one.
Apparently, for years, even decades, only tests of clinical options were allowed to proceed, basically because the government considers Americans to be infants:
There was great concern that the patient receive proper counseling, both before and after the test. The patient needed to appreciate the possibility of false positives, so he wouldn't panic unnecessarily if he got one. He needed to appreciate the danger of false negatives, so he wouldn't become reckless, endangering sexual partners. And he needed to understand the options and support groups available in the event he received a true positive. (On top of all these concerns, many AIDS activists at the time were opposed to almost any form of HIV testing out of fear that results could be used to ostracize and persecute HIV-positive people—though one hopes that public health concerns were paramount to the FDA, rather than political pressure and hysteria.)
blokeinfrance:
For the first time I'm with the government on this. The false positive / negative rate is absolutely crucial to any test and home testing is a really poor way of testing for something so serious.
July 10, 2012, 2:55 pmHow many of us go for prostate screening? How many for breast screening? Same unreliability of the tests, but the rate here is about 1:50.
Barak A. Pearlmutter:
@blokeinfrance, Maybe you'd be more comfortable if people were required to pass a simple statistical test before being allowed to use such a test? Something trivial, just a basic application of Bayes Rule. "A drug test has a false positive rate of 0.1% and a false negative rate of 0.001%, about 1% of the population actually uses the drug, someone is picked at random and tested and the result is positive; what is the probability they are a user?"
Or, try asking that question to your GP...
July 10, 2012, 3:12 pmHartzman:
Some answers to questions asked by an independent investigator from Oyster consulting answered by George Hartzman on his Wells Fargo Whistleblower filing
http://hartzman.blogspot.com/2012/07/some-answers-to-questions-asked-by.html
July 10, 2012, 4:23 pmDaublin:
@bloke, you seem to have not read closely. The American government approved the test. It just took them 24 years to do it.
July 10, 2012, 4:59 pmme:
Argh. There is ugliness in regulated behavior every day. This one strikes me more than most; the idea that the state ought to protect individuals from too much truth rings all the wrong bells. A classic case of depriving smart, responsible and at least minimally informed people from the means to make their own choices out of fear that they represent a tiny minority and that the majority is better served by being kept in the dark.
July 11, 2012, 12:26 amPaavo Oja:
"The false positive / negative rate is absolutely crucial to any test and home testing is a really poor way of testing for something so serious."
I think HIV-test is literally a textbook example of neglecting the base rate. The base rate is of course dependent on who end up using the test. Generally it is not advisable for everyone to test for equally unlikely conditions with similar false positive rates. The marketing might be harmful to general happiness of the populace.
Most Americans and everycountrians are of course infants when it comes to matters like these and marketing might lead to very unhappy results in the short run.
People probably shouldn't self administer HIV or cancer tests. If there are no legal restrictions then there should be social taboos preventing people from harming themselves. For every new thing there might not be social taboos, and a lot of people might get hurt by a hysteria caused by marketing and a newly legalized practice
July 11, 2012, 6:27 amInnumerate:
OK, Barak A., can you fill us in? Seems like about 90%, but I can't pass the test.
July 11, 2012, 6:53 ama_random_guy:
@Innumerate: It's about 50%. Assume you have 1000 people. 1% of them are actually drug users, so that's 10 people. The false negative rate is so small we can ignore it. Of the other 990, 0.1% of them or 9.9 will get a false positive. So out of 1000 people, approximately 20 will test positive, but half of those are false results.
The problem gets a lot worse as the percentage of true positive decreases. This HIV-test will be pretty good in "at risk" populations. However, among heterosexuals who are pretty good about practicing safe-sex, the vast majority of the positive results will be wrong, causing a lot of anguish and worry for no good reason.
July 11, 2012, 8:26 amorion:
"@Innumerate: It’s about 50%. Assume you have 1000 people. 1% of them are actually drug users, so that’s 10 people. The false negative rate is so small we can ignore it. Of the other 990, 0.1% of them or 9.9 will get a false positive. So out of 1000 people, approximately 20 will test positive, but half of those are false results."
Seems to me that this same logic is used by cops and prosecutors to justify their tactics in the "war on drugs". Insert arrests in place of negative and pretend its a SWAT team and change the context. The false arrests are insignificant in the face of the menace to society caused by drugs.
July 11, 2012, 9:47 amRocky:
If you were to take this test and it were to be positive, would you not take another and if were positive x2, would you not consult a Dr. before engaging in sexual activity or slashing your wrists out of despair? For God sake, I would be getting myself on down to the clinic for a professional opinion, wouldn't you?
July 11, 2012, 11:59 amDale:
(
1. However, among heterosexuals who are pretty good about practicing safe-sex, the vast majority of the positive results will be wrong, causing a lot of anguish and worry for no good reason.
)
The only people who would spend $60.00 on this test are people who have good reason to be concerned. Nobody is going to go to the drug store and say to themselves “hay this is something I can spend $60. on and it might be fun.
July 11, 2012, 1:52 pmDoctorT:
One side effects of the FDA's reluctance to allow home HIV testing is that people found a free method for getting tested: denying risky activities (homosexual sex, IV drug use, sex with prostitutes, etc.) and donating blood. All donated units are tested for HIV. If a blood unit is positive, the donor is notified confidentially. The problem is that the screening test isn't perfect, and some HIV positive blood has been accepted and transfused. Blood donation centers worked hard to discourage those at risk for HIV from using donation as a testing method. That only worked if there was access to a free clinic for HIV testing.
@blokeinfrance: The false positive/false negative issue exists regardless of test venue. The only thing lacking in the home test is immediate face-to-face access to counseling by a clinician. I believe (based on two decades of experience as a medical lab director) that users of home tests typically are wise enough to understand a report that says the HIV screening test is positive, but you need a confirmatory test.
@Dale: Heterosexuals practicing safe sex are not the target audience for the home HIV test. You are correct that when a person with a low likelihood of disease gets tested, almost all positive results are false positives. Does that mean that no one should be able to buy the test kit?
July 11, 2012, 2:40 pmDale:
DoctorT,
No, I'm all for the home test. I just thought that the argument about false positives was misguided.
July 11, 2012, 3:35 pmjoshv:
a_random_guy has it exactly right, in populations that are not at risk, HIV testing is insanity, as most positives will be false. There is no good reason for heterosexuals who don't use drugs to ever get an HIV test.
So your point about government not trusting the general populace is a bit beside the point, the government didn't want the general public taking a test that was wrong most of the time it told you that you had HIV.
July 11, 2012, 7:01 pmGryphon315:
The whole false positive argument is a load of BS. People who don't have the risk factors are not going to run out and test themselves for HIV. That would be like a woman who has never had sex running out and grabbing a pregnancy test.
And even if she did do that, i am pretty sure the next srep after getting a positive on a home pregnancy test is to go see a doctor.
July 11, 2012, 7:29 pma_random_guy:
People who don’t have the risk factors are not going to run out and test themselves for HIV. * * * ...i am pretty sure the next srep after getting a positive on a home pregnancy test is to go see a doctor.
First, precisely the people who are responsible about sex may choose to have an HIV test. My wife and I both did, before we got married and started a family. Neither of us were virgins, and we thought "unlikely, but better to check".
Second, yes, the right thing to do with a positive result is to go to a doctor and get a far more accurate test done. The problem is: most people have no clue about statistics and false positives. They may well take the test, get a positive result, and assume that the result is definitive.
That's not to say that the test should be restricted. However, you absolutely should expect to see it misused and misinterpreted.
July 12, 2012, 3:04 am