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Reason why CDC/FDA does not approve PCR test.
Hi Guys,
I was talking to a counselor from one of those online services that offer DNA PCR test.
He told me that most people will test +ve within 72 hours to 1 week of the infection.
He also said, the reason why people are asked to wait 28 days prior to testing is coz they want to cover everyone in the population..that is everyone between a new born baby to a 90 year old with serious cancer condition who is on the hospital bed.
He said after 28 days the test is indeed conclusive.
When I asked him then why is the PCR DNA not approved by the FDA.
He told me that FDA approves only those tests that will be used for the purpose of insurance.
Since the DNA PCR test is very expensive insurance companies don't want to bring up the cost of health care coz otherwise everyone will start testing on the DNA PCR test everytime they have sex or fear they have HIV.
Given that there is a cost effective EIA antibody test...FDA rather have you take that instead.
Further the counselor reassured me that a 28 day DNA PCR test is indeed conclusive anf that one would need no furthet testing after that !
What do you guys think about this ?
I was talking to a counselor from one of those online services that offer DNA PCR test.
He told me that most people will test +ve within 72 hours to 1 week of the infection.
He also said, the reason why people are asked to wait 28 days prior to testing is coz they want to cover everyone in the population..that is everyone between a new born baby to a 90 year old with serious cancer condition who is on the hospital bed.
He said after 28 days the test is indeed conclusive.
When I asked him then why is the PCR DNA not approved by the FDA.
He told me that FDA approves only those tests that will be used for the purpose of insurance.
Since the DNA PCR test is very expensive insurance companies don't want to bring up the cost of health care coz otherwise everyone will start testing on the DNA PCR test everytime they have sex or fear they have HIV.
Given that there is a cost effective EIA antibody test...FDA rather have you take that instead.
Further the counselor reassured me that a 28 day DNA PCR test is indeed conclusive anf that one would need no furthet testing after that !
What do you guys think about this ?
As far as PCR DNA or RNA test goes it costs from $150-250 depending on where you are in the country, at least in here in LA area I have been told this is the rate. Some places yeah they quoted me like $299, 350, 420, 650$ for same thing but really go through your doctor. Because not all these online referral places will send you the final lab report. And then you have to worry hoping you were not cheated. It is 2 bad that you cannot go directly and just order the test from the lab directly by passing the doctor who will charge you $150 for a 5 minute visit and write you a prescription. It seems like Lab Corp and Quest Diagnostics are the two major US labs probably better to use them for this type of test. Because yeah it is a complex test.
None of the PCR tests uses for "diagnosis" are stand alone tests (and aren't approved for diagnostic purposes anyway). In other words, even the PCR RNA test which is FDA approved will not be used as a stand alone diagnostic test. In most cases, testing companies will still tell you to antibody test as the final conclusive test.
Understand this: testing companies market these tests to a bunch of people who don't need it, shouldn't have it and then they turn around and tell you to get an antibody test anyway. Well, OK then.
As I said before, if you have the cash, and want to spend it, then go ahead, though you probably are wasting your money. While there isn't a constitutional right that you get a PCR test, if you have the cash, no one can stop you. Be prepared, though, to potentially suffer from a false positive. And that, from what I gather, isn't much fun.
My question is: how many of the people who get PCR tests here actually feel they are conclusive? They may feel better for a day or two, but then, after that?
I would have actually moved on. But since the prostitute was from Korea, and I have oral thrush 27 days, (pseudomembranias candiditis or something my doc told me) it is getting better, but I tell you it is terrifying to see... maybe post antibiotic related, then I wouldn't have worried. I am concerned with HIV-2, or some rare subtype. That is why I am like that... freaking out. And now this second day something is happening with my voice... hoarseness
Thanks Ronnie.
That has been our ongoing debate here.
Whether to use or not to use the PCR DNA.
That has been our ongoing debate here.
Whether to use or not to use the PCR DNA.
Just one comment regarding some of the posts earlier in the thread. There is more than one type of HIV PCR test. There is is a PCR HIV RNA test that is also known as the "viral load" test. This type of PCR test is indeed used primarily in the treatment monitoring of HIV positive patients as noted in the thread, although it can also be used for diagnosing HIV. The other type of HIV PCR test is the PCR DNA test which is not a viral load test, and the results for this test come back either "HIV detected" or "HIV not detected". Therefore, the PCR DNA test is not a viral load test and its only purpose is for diagnosis. Note (so there is no confusion here), just because the PCR DNA test is a diagnostic test, this does not mean that it is FDA approved as a general HIV diagnosis test for the population as a while, it is not. Its use in HIV diagnosis is for specific types of instances including for newborns of HIV+ mothers, rape victims, and a few other reasons. That does not mean that a lot of people worried about a recent HIV exposure do not use the PCR DNA test, but it is very expensive and has a relatively high rate of false positives.
Just a point on the false positives of PCR testing. If someone has had a low risk exposure, say unprotected oral sex with a theoretical chance of HIV transmission at 1/10000, but the false positives in the PCR test are 1/100, it is not really surprising that generally, the PCR test is not advised because you're 100x more likely to get a false positive than have caught HIV. I think that may be another reason why the general advice, irrespective of expense and the impact of insurance companies, is to back up with multiple other tests at a later date...
Hey Brian,
Like I said B4..there are many reasons for the government/CDC/FDA to ristrict the use of this test
e.g.
1.) Cost of healthcare - I presume u knonw the burden of health care cost in this country...it's just us worried wells on this forum but imagine the number of WW's out there who wud wanna test using such expensive methods...just imagine the impact on health care
2.) Range of Population - I remember reading something on thebody.com..when it comes to matters of health....the CDC does not want to take even a 0.0001% chance coz it is a matter of life. The PCR test may not be as useful in some members of the population due to pre-existing health conditions...hence test not approved.
While checking the quality of condoms The FDA, for example, recognises domestic and international standards that specify that the rate of sampled condoms failing the water leak test, for each manufacturing lot of condoms, be less than 1 condom in 400 (http://www.avert.org/condoms.htm)
NOW that is < 0.25 %
So you see how a tiny % makes a huge difference
3.) PCR test is prescribed for people who have repeated +ve or unclear results with antibodies or other test...what does this tell us...that eventually the PCR test WILL detect the virus.
4.) Pregneant women take this test coz they cant wait for 3 months to see if they are +ve....so if this result can be used on them...why not us worried folks ?
Like I said B4..there are many reasons for the government/CDC/FDA to ristrict the use of this test
e.g.
1.) Cost of healthcare - I presume u knonw the burden of health care cost in this country...it's just us worried wells on this forum but imagine the number of WW's out there who wud wanna test using such expensive methods...just imagine the impact on health care
2.) Range of Population - I remember reading something on thebody.com..when it comes to matters of health....the CDC does not want to take even a 0.0001% chance coz it is a matter of life. The PCR test may not be as useful in some members of the population due to pre-existing health conditions...hence test not approved.
While checking the quality of condoms The FDA, for example, recognises domestic and international standards that specify that the rate of sampled condoms failing the water leak test, for each manufacturing lot of condoms, be less than 1 condom in 400 (http://www.avert.org/condoms.htm)
NOW that is < 0.25 %
So you see how a tiny % makes a huge difference
3.) PCR test is prescribed for people who have repeated +ve or unclear results with antibodies or other test...what does this tell us...that eventually the PCR test WILL detect the virus.
4.) Pregneant women take this test coz they cant wait for 3 months to see if they are +ve....so if this result can be used on them...why not us worried folks ?
>So please guys don't bash the PCR tests, really stop it!, people have the right to get the best possible tests. PCR's are not perfect... but best there is so far in early detection.
A: Not sure I was "bashing" the test, only giving my reasons against it. If you disagree, that is up to you. In the end, everyone has the absolute right to get any test they want. The question wasn't do I have the right to get it, though, the question was should I get it. In the case of the original poster, my answer still stands: absolutely not. It is not needed, it is not warranted, and it should not be done.
Lex,
You are right...my neighbor is a professor at a very well known university.
He told me that doctors and insurance companies have a very very strong lobby.
He told me that the Dr. fees are going up each year coz they pay a lot of the presidential campaigns.
He also told me that on drug company (phizer or merck i don
You are right...my neighbor is a professor at a very well known university.
He told me that doctors and insurance companies have a very very strong lobby.
He told me that the Dr. fees are going up each year coz they pay a lot of the presidential campaigns.
He also told me that on drug company (phizer or merck i don
Then again, perhaps the tests are meant for a specific group of patients, and you do not fall into that specific group. Especially given the fact that your encounter did not leave you at any risk of contracting HIV in the first place.
In the end, it's your right to spend 300 or 600 or 900 on a series of tests that you really don't need. You can do it, and no on can stop you. But there are plenty of people here with prior experience who might try to give you the benefit of their accrued wisdom. Whether you listen or not is strictly up to you.
It's hard when you're freaking about HIV, I know. So I would never judge anyone who got the test very harshly. Just trying to point out that you really don't need it.
In any event, good luck to you.
Let's try to remove subjective and judgmental words from our discourse here. The emotions are running high enough.
No one here is "bashing" PCR tests. It's also ludicrous to say that PCR tests are "the best" or are "better than" antibody tests. They are very different tests, so comparing them (in an absolute fashion) is erroneous.
My original point (and that of others, including Dr Bob, Dr HHH) still stands. There are MEDICAL/SCIENTIFIC reasons why the PCR test is not the most appropriate choice when attempting to diagnose HIV serostatus. Yes, if a patient has a NEGATIVE PCR at 28 days post exposure, then the patient is concluded to be negative (assuming they're not on PEP).
If the PCR is POSITIVE, however, the patient is not assumed to be positive due to the lower specificity of the test.
The ELISA+Western blot combination for antibody testing, however, is specifically designed to diagnosis and to rule out false postiives and negatives (outside the window period).
Now, regardless of the politics involved, there are LEGITIMATE public policy concerns regarding the use of the PCR test, which is PART of the reason (the other part being medical) that the CDC doesn't recommend the use of PCR for absolute diagnosis.
I also disagree that a patient should 'get any test that they want' free of charge. Most patients make a number of irrational demands.
For example, I have Addison's disease (primary adrenal cortex failure). One of the main tests used to diagnose the disease and monitor patient health is the ACTH test (adreno corticotrophic hormone). The ACTH test is very expensive ($1200) and complicated. But doctors should prescribe it only when appropriate, not just because a patient THINKS they might have it (Addison's is rare, by the way, affecting roughly 1/100,000 people).
PCR tests have their place, and doctors have the discretion to prescribe them as they see fit. And patients are free to request them. But from a medical and public policy standpoint, widespread use of PCR tests is not appropriate or advised.
No one here is "bashing" PCR tests. It's also ludicrous to say that PCR tests are "the best" or are "better than" antibody tests. They are very different tests, so comparing them (in an absolute fashion) is erroneous.
My original point (and that of others, including Dr Bob, Dr HHH) still stands. There are MEDICAL/SCIENTIFIC reasons why the PCR test is not the most appropriate choice when attempting to diagnose HIV serostatus. Yes, if a patient has a NEGATIVE PCR at 28 days post exposure, then the patient is concluded to be negative (assuming they're not on PEP).
If the PCR is POSITIVE, however, the patient is not assumed to be positive due to the lower specificity of the test.
The ELISA+Western blot combination for antibody testing, however, is specifically designed to diagnosis and to rule out false postiives and negatives (outside the window period).
Now, regardless of the politics involved, there are LEGITIMATE public policy concerns regarding the use of the PCR test, which is PART of the reason (the other part being medical) that the CDC doesn't recommend the use of PCR for absolute diagnosis.
I also disagree that a patient should 'get any test that they want' free of charge. Most patients make a number of irrational demands.
For example, I have Addison's disease (primary adrenal cortex failure). One of the main tests used to diagnose the disease and monitor patient health is the ACTH test (adreno corticotrophic hormone). The ACTH test is very expensive ($1200) and complicated. But doctors should prescribe it only when appropriate, not just because a patient THINKS they might have it (Addison's is rare, by the way, affecting roughly 1/100,000 people).
PCR tests have their place, and doctors have the discretion to prescribe them as they see fit. And patients are free to request them. But from a medical and public policy standpoint, widespread use of PCR tests is not appropriate or advised.
OK
This is what I have come to conclude
DNA = Deoxyribo nucleic acid (NUCLEIC ACID)
Therefore a DNA PCR test is a NAAT test
Since 2001, donated blood in the United States has been screened with nucleic-acid-based tests, shortening the window period between infection and detectability of disease to about 12 days (http://en.wikipedia.org/wiki/HIV_test#Nucleic_acid_based_tests_.28NAT.29)
NOW, here is proof that CDC has approved the NAAT test
http://www.fda.gov/bbs/topics/ANSWERS/2001/ANS01103.html
This is what I have come to conclude
DNA = Deoxyribo nucleic acid (NUCLEIC ACID)
Therefore a DNA PCR test is a NAAT test
Since 2001, donated blood in the United States has been screened with nucleic-acid-based tests, shortening the window period between infection and detectability of disease to about 12 days (http://en.wikipedia.org/wiki/HIV_test#Nucleic_acid_based_tests_.28NAT.29)
NOW, here is proof that CDC has approved the NAAT test
http://www.fda.gov/bbs/topics/ANSWERS/2001/ANS01103.html
VERY TRUE.
If the American Red Cross and other blood banks are able to screen the general population and screen the blood in a matter of days....then I guess ...and I say.."guess", you clearly must be right.
Why would the gov't , in this day and age, jeopardize the population of the US citizens blood supply and cause financial hardship for the American Red Cross by offering expensive testing measures for screening blood banks?
They must get a discount! LOL
EXAMPLE:
A person has sex Jan. 1st with someone who is HIV+
January 15th the person donates blood.
How does the A.R.C. know that this blood donor is not +ve?
They must have SOMETHING in place for instances like this.
You cannot rely solely on someone's word that they are HIV-, and when the last time they slept with someone.
Need some valid feedback.
If the American Red Cross and other blood banks are able to screen the general population and screen the blood in a matter of days....then I guess ...and I say.."guess", you clearly must be right.
Why would the gov't , in this day and age, jeopardize the population of the US citizens blood supply and cause financial hardship for the American Red Cross by offering expensive testing measures for screening blood banks?
They must get a discount! LOL
EXAMPLE:
A person has sex Jan. 1st with someone who is HIV+
January 15th the person donates blood.
How does the A.R.C. know that this blood donor is not +ve?
They must have SOMETHING in place for instances like this.
You cannot rely solely on someone's word that they are HIV-, and when the last time they slept with someone.
Need some valid feedback.
Three reasons why DNA PCR is not approved by CDC!
1) It's expensive (299-399) per test
2) Since it is a highly sensitive test, the percentagee of getting a false positive is higher than other tests, at which point you will completely freak out even though you're most likely negative.
3) You'll most likely wait till 28 days to take the test. At 28 days, majority of the population will test positive by a simple antibody test if they are in fact infected. Thus, why spend $399 on a DNA PCR when you can get an antibody test done at low costs.
It's completely up to you. In my situation, I took the DNA PCR and was negative. It did make me feel better, but I still tested with the antibody test at 12 weeks just to ensure myself. Good luck
1) It's expensive (299-399) per test
2) Since it is a highly sensitive test, the percentagee of getting a false positive is higher than other tests, at which point you will completely freak out even though you're most likely negative.
3) You'll most likely wait till 28 days to take the test. At 28 days, majority of the population will test positive by a simple antibody test if they are in fact infected. Thus, why spend $399 on a DNA PCR when you can get an antibody test done at low costs.
It's completely up to you. In my situation, I took the DNA PCR and was negative. It did make me feel better, but I still tested with the antibody test at 12 weeks just to ensure myself. Good luck
http://en.wikipedia.org/wiki/American_Red_Cross#Nucleic_Acid_Testing
Check this out as well.
Thanks for info.
P.S. I do not care about cost of testing for PCR.
Peace of mind = Priceless
Check this out as well.
Thanks for info.
P.S. I do not care about cost of testing for PCR.
Peace of mind = Priceless
NAAT testing IS used for blood supplies. HOWEVER, KEEP IN MIND THAT THE RED CROSS IS NOT DIAGNOSING ANYONE!!!
When a NAT test on a particular donor's blood shows positive, the blood is discarded and the donor is notified. The Red Cross doesn't worry about "false positives"; they reject the blood anyway.
Once the donor is notified, however, the donor is advised to follow-up with their own PCP for diagnosis. DIAGNOSIS OF THE DONOR IS DONE WITH ELISA + WESTERN BLOT.
So, enough already with the ridiculous conspiracy theories about the government and insurance lobbies trying to keep patients from getting access to the "best" test. The tests server different purposes, and there are clear reasons why the antibody tests are the tests of choice for actual sero-diagnosis.
When a NAT test on a particular donor's blood shows positive, the blood is discarded and the donor is notified. The Red Cross doesn't worry about "false positives"; they reject the blood anyway.
Once the donor is notified, however, the donor is advised to follow-up with their own PCP for diagnosis. DIAGNOSIS OF THE DONOR IS DONE WITH ELISA + WESTERN BLOT.
So, enough already with the ridiculous conspiracy theories about the government and insurance lobbies trying to keep patients from getting access to the "best" test. The tests server different purposes, and there are clear reasons why the antibody tests are the tests of choice for actual sero-diagnosis.
http://caps.ucsf.edu/pubs/FS/acuteinfection.php
This article was quite interesting.
Not to mention that Dr. Klausner is one of MD HHH's friends.
This article was quite interesting.
Not to mention that Dr. Klausner is one of MD HHH's friends.
OK...I understand what ur saying that if the test is a +ve..it needs to be diagnosed by EIA + WB
However no one on this site is trying to get a +ve result.
If we get a -ve with these test we know for sure we are -ve as the DNA PCR is very SENSITIVE
the false +ve is due to the test's lack of SPECIFICITY
However no one on this site is trying to get a +ve result.
If we get a -ve with these test we know for sure we are -ve as the DNA PCR is very SENSITIVE
the false +ve is due to the test's lack of SPECIFICITY
"However no one on this site is trying to get a +ve result."
TRUE.
The only rationale would be having to deal with a false +ve for two more weeks until you test at the 6 week mark with a standard antibody test.
If you are negative @ 4 weeks, your rather solid for being -ve.
Am I right with this now?
TRUE.
The only rationale would be having to deal with a false +ve for two more weeks until you test at the 6 week mark with a standard antibody test.
If you are negative @ 4 weeks, your rather solid for being -ve.
Am I right with this now?
Brian never mind people that here constantly bash PCR testing technology. Look at this info it is from HIV symposium. And judge yourself. http://www.nchads.org/docs/Symposium/2006/Lab/Phillip%20Cunningham2.pdf Do your own research. Not just what "doctors" tell you. Doctors are human beings and make errors in judgment and may not have all the up to date info. And what your counselor told you was right. It is all about money precisely it is the insurance companies that are lobbying against these tests, believe me if you were some sort of an important person, celebrity, politician, athlete, they would do all those tests for you, not once but several times and in combination with one another. I mean the NAT's, p24 antigens in the PHI faze... your doctors would I mean. In the US health care sucks! It is unaffordable the government would rather spend 500 billion on the military rather then health care, or modern HIV testing clinics, where you could walk in and get everything done, using up to date testing technology, and the place wouldn't be dirty, and looking like a homeless shelter. The regular antibody tests are definitive from 3 months and above, because it really depends on the person. ~ 4-13weeks seems to be the majority for most people where they fall as far as HIV antibody detection, and I really really hope that all of us here in this 90% range, but it could be six moths as well or a year in some cases. So there is no debate here. The NAAT tests are conclusive after 28 days. But I agree they should be used in combination with other tests. The only thing is what sucks is that most places offer PCR HIV-1, that is what killing me.... it is hard to last 3 months, I am approaching 8 weeks mark and I am so paranoid over this HIV-2 possibility I lost the ability to think rationally. And that is what it does to you the longer you wait. Plus I had no prior knowledge on HIV as I am sure most us here did. So when I go to a doctor and I had symptoms one would think he/she would do all the tests that were in my best interest, and at least explain me the choices and different methodology these tests use. Instead of me uncovering all this info. And what really makes me angry all the doctors I wen to tell me " No you don't have HIV, but you should still test at 13 weeks just to be sure, You don't look like you have HIV" I am told, it is funny to them that i am like that. That makes no sense. How does one know if I don't have HIV by looking at me?
So please guys don't bash the PCR tests, really stop it!, people have the right to get the best possible tests. PCR's are not perfect... but best there is so far in early detection.
So please guys don't bash the PCR tests, really stop it!, people have the right to get the best possible tests. PCR's are not perfect... but best there is so far in early detection.
First, some terminology:
sensitivity: The percentage of the results that will be positive when HIV is present.
specificity: The percentage of the results that will be negative when HIV not present.
The PCR test is indeed highly sensitive. However, it is not as specific. This is why it is used primarily on patients who are KNOWN to be HIV+ by ELISA + Western-blot: there's no chance of a 'false-positive' in a PCR if the patient is known to be positive.
PCR is not recommended for diagnostic use because of the rate of false positives and the undue stress it would put on patients. And any false-positives would need to be verified with ELISA+Western blot before the patient would be considered HIV+.
Incidentally, the difference between sensitivity and specificity is the same reason for the use of ELISA with Western blot.
The ELISA test is extremely sensitive, but has slightly lower specificity. Consequently, someone who tests negative with ELISA is considered negative.
If someone tests positive with ELISA, the test is re-run. If a positive ELISA result is achieved the second time, the Western blot test is run. The Western blot test is highly SPECIFIC to HIV, but somewhat less sensitive. If and only if a patient tests positive (repeatedly) on ELISA and positive on Western blot are they then considered to be HIV+.
http://en.wikipedia.org/wiki/HIV_test
sensitivity: The percentage of the results that will be positive when HIV is present.
specificity: The percentage of the results that will be negative when HIV not present.
The PCR test is indeed highly sensitive. However, it is not as specific. This is why it is used primarily on patients who are KNOWN to be HIV+ by ELISA + Western-blot: there's no chance of a 'false-positive' in a PCR if the patient is known to be positive.
PCR is not recommended for diagnostic use because of the rate of false positives and the undue stress it would put on patients. And any false-positives would need to be verified with ELISA+Western blot before the patient would be considered HIV+.
Incidentally, the difference between sensitivity and specificity is the same reason for the use of ELISA with Western blot.
The ELISA test is extremely sensitive, but has slightly lower specificity. Consequently, someone who tests negative with ELISA is considered negative.
If someone tests positive with ELISA, the test is re-run. If a positive ELISA result is achieved the second time, the Western blot test is run. The Western blot test is highly SPECIFIC to HIV, but somewhat less sensitive. If and only if a patient tests positive (repeatedly) on ELISA and positive on Western blot are they then considered to be HIV+.
http://en.wikipedia.org/wiki/HIV_test
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