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Testing after PEP - Peculiar concerns (HEPATITIS C AND DELAYED HIV SEROCONVERSION, 2011) (APTIMA - HIV-1 RNA QUALITATIVE ASSAY, 2011) (p24 ANTIGEN TESTING, 2011)
Feb 15, 2011

Dear Doctor Fauscino

With my apologies if some of the questions below seem repetitive. I hope I do not upset you. There are some matters below that are somewhat distinct and I am hopeful you can add some additional clarity and/or confirmation to. Your forum has been very helpful so far and I have made a nice donation to your foundation a few weeks ago. I will be happy to continue even if these questions exacerbate you and you think I am being too bothersome. My anxiety and that of my partner is unfortunately very high because we live overseas and finding comprehensive knowledge is very challenging. We fly out to get certain tests.

We followed a 4-week course of PEP late last year. 3 and half weeks (24 days) after the end of PEP or 7 and half weeks after the potentially risky incident we had a HIV 1 & 2 Ab/p24 Ag and an HIV-1 RNA, Quant (PCR) done. The HIV Ab and p24 was negative and the RNA PCR was not detected. (The RNA PCR used was COBAS Ampliprep/Taqman HIV by Roche Molecular Systems, Inc.)

My question are as follows:

1.) How reliable or conclusive is this specific RNA PCR assuming 3 and half weeks after the end of PEP? I know it is not FDA-approved but some clinics do offer it as a matter of course. 2.) How about the p24 which has been approved in Europe? 3.) I have seen some information indicating that Hepatitis C co-infection could significantly delay the development of antibodies and we are concerned with the possibility of this happening too (liver panels have been showing increasing abnormal enzymes). Would such an occurrence also affect a RNA PCR Test or would this kind of test be able to see through this problem and give reliable information irrespective of this possibility. (I have also inquired about this and other Hepatitis concerns with Doctor McGovern.) 4.) Finally why do some clinics offer RNA PCR test when there is an official reluctance to make it a formal diagnostic test? Is it just a matter of cost and/or false-positives? What is the downside?

I intend to follow the official recommendations and get tested again at 3 months and 6 months. If there some clarifications you can give now on the questions above, we would be very grateful.

Thank you for all your care and understanding

Response from Dr. Frascino

Hello,

No apology is necessary. I've answered so may questions in this forum over the years that greater than 99% of the questions I respond to on a daily basis I've already addressed (many multiple times). Responding to your specific questions:

1. Certainly any negative or undetectable HIV test is encouraging; however, we have no specific statistics on "how reliable" a quantitative HIV RNA PCR is 3.5 weeks after completing a course of PEP. As you note, this type of test is not FDA approved for diagnostic purposes.

2. The p24 antigen test often causes confusion. P24 antigen is one of HIV's core proteins. It surrounds the viral RNA. When HIV is madly replicating, as in early HIV infection, p24 antigen (a protein) is produced in massive quantities. It can then be detected in the blood. It is a reasonably good marker of acute infection, but dissipates over a period of several weeks as p24 antibodies begin to develop. Consequently it's not helpful in diagnosing HIV infection after several weeks. It would not be helpful in your case.

3. See below for information from the archives related to HIV/hepatitis C co-infection and delayed seroconversion. HIV RNA PCR testing assays for a piece of the virus's genetic material and has nothing to do with anti-HIV antibodies. Concurrent hepatitis C infection would not affect HIV RNA PCR or HIV DNA PCR (quantitative or qualitative assays),

4. There are multiple concerns, including the rate of false positives, other technical considerations, availability and cost. Only one HIV RNA PCR test has been FDA approved for HIV diagnostic testing -- the APTIMA. It's a qualitative test. See below.

I agree you should follow the published guidelines for post-PEP HIV-antibody testing.

Thank you for your support of The Robert James Frascino AIDS Foundation (www.concertedeffort.org). It's warmly appreciated. In return I'm sending you my best good-luck karma that your definitive post-PEP HIV tests remain negative. The odds are very much in your favor that they will.

Good luck.

Dr. Bob

I REALLY NEED YOU!!!! (HEPATITIS C AND DELAYED HIV SEROCONVERSION) May 20, 2008

Dr. Bob,

I asked you awhile back if HEP C would delay HIV seroconversion.

You said that HEP C would not delay HIV seroconversion! However, Dr. McGovern of the body says that HEP C will delay the HIV window period and that someone who was exposed to both should wait until 6 months to 1 year!!!! Before getting a result!

What's up with that????

Now I know my risk (sharing dollar bill to sniff cocaine) was a low risk incident but what should I do????

I got tested for HEP C at 14 weeks....NEGATIVE!

And HIV at 15 and 17 weeks!!!! NEGATIVE

What should I do???? I think that I am ok and then I hear this stuff!?

Response from Dr. Frascino

Hello,

No, you don't really need me! What you really need is to pay more attention to what both Dr. McGovern and I have told you on multiple occasions: You are HIV negative. I may need to put a restraining order out on you if you continue to ask your same question over and over again in multiple forums. Come on guy! Give it up! Accept the truly wonderful news you're HIV negative and give other worriers a chance to have their concerns addressed, OK?

This is the last time I'm going to go over this information with you, so pay attention! The Centers for Disease Control has published guidelines for health care workers who sustain a significant occupational exposure to a patient coinfected with HIV and hepatitis C viruses. (This is a far cry from snorting coke through a rolled-up Ben Franklin!) The health care worker guidelines for occupational exposure to coinfected patients suggest HIV-antibody testing at baseline, six weeks and twelve weeks after exposure. There is a caveat, however: If, and I must stress this "if," the health care worker develops acute hepatitis C infection, then and only then (I also stress the "then and only then") would additional HIV-antibody testing be recommend. In this case, and only in this case, are HIV tests out to 12 months recommended. Put another way, if the health care worker does not get ill with acute hepatitis C infection, additional tests would not be recommended!

You have tested hepatitis C negative out to 14 weeks. You do not have acute hepatitis C infection. Hence even if you were a health care worker with documented significant exposure to a coinfected patient, you would not need additional HIV testing. I just can't make it any plainer or clearer than that. Those are the facts, plain and simple. How you choose to live with the incontrovertible evidence that you do not have hepatitis C and that you are conclusively HIV negative is now up to you.

So, I'm signing off on this case permanently. If you require additional reassurance, you can either reread my many (too many) responses to your repetitive and ongoing unwarranted worries or you can seek psychological help. Your problem is not virological; it's psychological!

I'll repost Dr. McGovern's and my responses to you below. We are in absolute agreement!

Dr. Bob

Can you please tell me if my test results are conclusive???? May 9, 2008

Hello, I emailed you a few weeks ago about sharing a dollar bill to sniff cocaine!( Since I have never touched the stuff!!!!)

Anyway, I got a blood test from my doctor and my test came out negative!!!! This was 14 weeks after sharing the dollar bill.

I also got tested for HIV and that was negative!!!!

So in conclusion, would you say that my negative test results are conclusive? Can I forget all about this?

Response from Dr. McGovern

The risk of HCV transmission through sharing a dollar bill is very low. With this negative blood test, I would suggest that you have had adequate testing.

Remember also that cocaine can lead to heart attacks.

Dr. Bob 3rd time asking......donation coming if you answer! Feb 11, 2008

Dr, Bob I hope you answer this Dr. Bob because I have asked numerous times....

My only fears involving HIV is that I shared a dollar bill to sniff cocaine with a group of people...what would the chances be of getting HIV from this? Has it ever happened? What if there was blood on the dollar bill and I didn't notice? Should I get tested? Not due to fears but scientifically speaking.

My second question is....is it possible to get HIV from deep kissing? I have a moderate case of Gingivitis? I was out drinking alcohol and made out with a girl. What are the chances? I know it happened once right? With that married couple in 1997?

Oh and are 3 month tests conclusive?

Please help and I will send a donation!

Response from Dr. Frascino

Hello,

1. Theoretical chances of contracting HIV via rolled-up-dollar-bill coke sniffing would be negligible to nonexistent. Has it ever happened? Not to my knowledge. However, please note we haven't run studies on this, as the Investigative Review Board and ethics committee would tend to frown on such a clinical trial. Testing would be primarily to put your residual fears permanently to rest.

2. Kissing is not considered to be a significant risk for HIV transmission, even with a moderate case of gingivitis. Once again, if you're worried, get tested! You'll have an accurate result in less than 20 minutes with a rapid test.

3. Yep, three months is conclusive, unless there are extenuating circumstances.

Thanks for your donation (www.concertedeffort.org).

One final piece of advice: Things don't go better with coke! I recommend strongly you stop.

Be well.

Dr. Bob

60 bucks already in the mailbox!!!!.....Last question....is my test conclusive? Apr 13, 2008

Dr. Bob, Hello Dr. Bob! I hope everything is going well with you! I just donated 60 bucks, (I am a college student, and thats the best I can do right now) But I will remember to always donate to your foundation in the future. I put the cash in an envelope and sent it this afternoon. Can you answer my 3 last questions?

Just so you know....I am the guy who shared a dollar bill with some people to sniff cocaine some 12 weeks back. Here are my questions.

1) I got a test today and today was 84 days since I shared the dollar bill to sniff coke. I had an oraquick mouth swab test and it came out negative? Am I ok? Can I finally put this behind me? I tested at 6, 8, 10, and 12 weeks, all negative.

2) Are you sure 12 weeks is conclusive? It's not technically 90 days but its 84 or 85. So am I ok? And can you explain why 12 weeks is ok?

3) Also, is French kissing a risk? My gums bleed sometimes and I french kissed a girl at the bar. Does this warrant testing? That was 9 weeks ago!

Again thank you so much for everything! You truly are a great person and I wish nothing but the best for you!!!!!

Response from Dr. Frascino

Hey College-Guy,

1. Yes! Your repeatedly negative HIV tests out to 12 weeks are conclusive and definitive. HIV is not your problem. No way. No how. WOO-HOO!

2. Exactly which part of "No way. No how. WOO-HOO!" are you having difficulty understanding? The published guidelines indicate a negative test at three months is definitive. Twelve weeks equals three months. Consequently you are OK, OK?

3. As the old son goes, "You must remember this, a kiss is just a kiss, as time goes by . . . ." Testing is not warranted. As for your bleeding gums, see your dentist and don't forget to floss!

Thanks for your tax-deductible gift to the Robert James Frascino AIDS Foundation (www.concertedeffort.org).

Be well. Stay well. (Stay away from the nose candy!)

Dr. Bob

I WANT TO GET MARRIED!!!! DON'T HATE ME! May 11, 2008

Dr. Bob, I am so sorry to bother you again! I forget to ask a question in my last post!

I was hoping you could clear something up for me because I was confused from your response.....so just 1 question please! I want to marry my gf and I need to know this before I can!

I am the guy who asked you about the risk of sharing a dollar bill to sniff cocaine/ and french kissing with gingivitis! (Please answer last question forever!!!!)

Now just to jog your memory....shared dollar bill to sniff cocaine with group of people/ waited 15 weeks...test NEGATIVE!!!!!

Kissing with Gingivits....waited 12 weeks....test NEGATIVE!!!!

Both tests were ORAQUICK!

Do I need to retest at 6 months, or is my 15 week and 12 week tests conclusive???? Sometimes you say 6 months....is this one of those cases?

I want to get married but need to know this! I am sorry for asking again!!!!

Response from Dr. Frascino

Hi,

Maybe you shouldn't make those "last question forever" type statements. Something tells me you're more of a "hey doc, I just thought of another question" type of guy.

Regarding your latest question, your negative results are definitive and conclusive. No additional testing is warranted.

Congratulations on the upcoming nuptials!

Be well. Stay well.

Dr. Bob

APTIMA HIV-1 RNA QUALITATIVE ASSAY (APTIMA - HIV-1 RNA QUALITATIVE ASSAY, 2010) Part 2 Dec 5, 2010

To the good Dr. Bob,

I have submitted a donation on-line, and will submit a heftier holiday donation as well, but in the interim I was hoping you might field another inquiry from me regarding a post of mine a few weeks ago pertaining to the Aptima HIV 1 RNA Qualitative Assay. I have a bit more specific questions regarding the general replication of the HIV virus with reference to RNA copies per milliliter during the first several weeks/months after infection.

I've read the package insert for the Gen-Probe Aptima HIV 1 RNA Qualitative Assay with regards to their own study of clinical sensitivity. The study involved 1,041 specimens from four commercial vendors (867 for HIV-1 only and 174 for HIV-1 & HCV). Very important to note of course, during the study, specimens known to contain less than 100 copies/ml of viral RNA were excluded from the analysis and therefore the sensitivity cited was for samples with viral RNA concentration equal to or greater than 100 copies/ml. On all 1,041 specimens, the assay returned reactive results; or 100% for Gen-Probe's particular study.

Analytical sensitivity was also performed by serial dilution of negative human plasma spiked with HIV-1. This study yielded 100% reactive results at 300 copies/ml (715/715), 100% reactive results at 100 copies/ml (718/718), 98.5% reactive results at 30 copies/ml (702/713), 82.6% reactive at 10 copies/ml (592/717), 42.5% at 3 copies/ml (305/717) and 19.4% at 1 copy/ml (139/718).

Understanding that viremia and HIV viral replication is likely very different from one person to the next, however also assuming there have been studies performed on the "average" viral replication after acute infection which you would likely be very familiar with, and considering I received a non-reactive qualitative RNA test at 32 days post potential exposure, I have the following questions:

1) What is the likelihood, if infected, a person would have less than 100 copies/ml of HIV RNA, or even 30 copies/ml, after one month post exposure? I read in one study posted on The Body the following: "On entry to the study, the median duration of HIV infection for those with acute HIV was estimated to be 28 days. At the initial screening visit, blood viral load was significantly higher in men with acute HIV (1,000,000 copies/ml) than men with chronic HIV (100,000 copies/ml)".

I also read on the Johns Hopkins HIV guide the following: "the range of RNA copies/ml can be very wide during acute infection. If the blood is obtained during the symptomatic phase and not everyone is symptomatic, the viral load can be between 100,000 and ten million. It can even be as high as 90 million copies/ml. If the blood is obtained from the individual after seroconversion, the viral load may be as low as 1,000 copies to as high as 500,000 copies."

2) If a person becomes infected, quickly seroconverts and develops antibodies, is it possible that without interference (i.e. no antiretrovirals or PEP) the virus could have spiked already and then been suppressed to under 100 copies/ml of HIV RNA by the body's natural immune system within a month's time - or any amount of time for that matter? In other words, if an RNA qualitative assay becomes reactive within a month, would you expect it to permanently remain reactive without the use of antiretrovirals? I believe I read somewhere, and it wasn't a doctor that posted the information, that if you're going to take a PCR, a DNA PCR is better post 28 days than the RNA PCR because of the potential of the body's natural immune system to suppress the virus to undetectable levels. However with what I've read about the virus, that doesn't seem very plausible. So now I'm confused and wondering if I took the right test or waited too long for the RNA PCR to be accurate at 32 days. What is your opinion?

3) If one is/was presenting with potential ARS syptoms, would you expect that the viral load should then be high enough to produce a reactive result on a qualitative RNA PCR at that time?

4) I read on the CDC the following "Another type of test is an RNA test, which detects the HIV virus directly. The time between HIV infection and RNA detection is 9-11 days." I also read on AVERT the following: "A PCR test can detect the genetic material of HIV rather than the antibodies to the virus, and so can identify HIV in the blood within two or three weeks of infection." So aside from price (which I've already paid), and the chance of a false positive (which didn't occur), what is the downfall of the test for me at this point in time? False negative due to low viral amounts? Technical error? Is my non-reactive result at 32 days pretty reliable? Dr. Bob, I've read your words over and over in the post you provided me stating if a four-week Aptima PCR is undetectable, it would be extremely extremely unlikely a three-month HIV antibody test would be reactive in your experience. Can I relax? The infectious disease doctor performing the test advised that with my one-time exposure risk, combined with the non-reactive qualitative PCR results post 32 days, I could be nearly 99.9% certain I wasn't infected, but for my own peace of mind, take the antibody test > three months.

5) Would any kind of drugs, besides antiretrovirals, or other co-infections, halt the replication of HIV RNA?

Sheesh!!! I've turned into a perpetual worrier...and questioner. Anxiety and stress are through the roof and taking their physical tolls. What do you recommend I do from here regarding testing? In your experience, how accurate do you think a negative qualitative PCR is one month post exposure? Any insights you can offer are, as always, greatly appreciated.

Warm regards and a happy and healthy holiday season to you and yours. Signed, Aptimistaken

Response from Dr. Frascino

Hi Aptimistaken,

You're going to qualify for an advanced degree in nucleic acid polymerase chain reaction laboratory analysis before long. Dude, it's time to turn off your inner scientific geek and come back to planet earth. I can't believe you actually read the Gen-Probe package insert for APTIMA HIV-1 RNA Qualitative Assay! That's got to be more painful than Palin's latest ghost-written babble.

I'll try to briefly respond to your many questions:

1. It would be very unlikely to have less than 30 or 100 copies/ml of HIV RNA one month after infection. I agree with what you read on The Body and on the Johns Hopkins HIV information site.

2. This would be extremely unlikely within a month's time. It can occur in the rare cases called "elite controllers." As for the "right test," the gold standard for HIV-diagnostic testing remains an HIV-antibody test taken outside the window period. The APTIMA HIV-1 RNA Qualitative Assay is the only nucleic acid test approved by the FDA for diagnostic testing.

3. Yes.

4. You don't really have a downside. False negatives are not a problem with PCR testing. Technical error is always possible, but extremely rare. I would assume your 32 day result is indeed "pretty reliable." I absolutely agree with the assessment and advice you received from the infectious disease physician.

5. Antiretroviral drugs can decrease HIV replication, thereby decreasing HIV RNA viral load levels. Co-infections or other drugs would not decrease HIV replication. (Please note HIV replication is quite different from anti-HIV-antibody production.)

If indeed your anxiety and stress are "through the roof" (and I agree they are!), you should seek help for this very real medical problem. Anti-anxiety medications and/or psychotherapy (counseling) can be extremely beneficial.

As for additional testing, I'd recommend you get a three-month HIV-antibody test primarily for peace of mind. I'm confident the result will be negative. As for the accuracy of qualitative PCR testing at one month, none of us have a great deal of personal experience in evaluating the sensitivity or specificity of this test at a specific point in time. As you can probably imagine, it would be difficult to evaluate as you would need to exactly when someone became infected and evaluate this testing technology against others, etc. I would trust the FDA recommendation and guidelines.

Thanks for your ongoing support of The Robert James Frascino AIDS Foundation (www.concertedeffort.org). It's very much appreciated during this holiday season. In return I'm sending you my best good-luck/good-health karma that you are now and will forever be HIV free!

Good luck and Happy Thankschristkwanzaakkah.

Dr. Bob

APTIMA HIV-1 RNA QUALITATIVE ASSAY (APTIMA - HIV-1 RNA QUALITATIVE ASSAY, 2010) Nov 18, 2010

Dear Dr. Bob,

I thank you kindly and sincerely for your efforts, support and the invaluable knowledge you provide to the questioners on this forum. I have been reading this website extensively (over a month now) since my potential exposure date, and have been wavering as to whether or not I should post a question; at least certainly not before being as proactive as I can on my end with the tests currently available to me given the elapsed time. I wont even delve into what I believe to have been the onset and continuation of many ARS symptoms as I recognize actual test results always eclipse symptoms, many of which Im optimistically contributing to stress and anxiety.

My exposure risk, being a male, is unprotected insertive vaginal sex with a female stripper. The circumstances are tired, regrettable and the same; bachelor party, Im not much of a drinker, went back for what I thought would be a lap dance and left the establishment with dreaded horror. I have no way of knowing this womans HIV status or of getting in contact with her. Every day is a living nightmare now especially considering the questionable CDC per act risk of exposure guidelines in light of the Kimberly Powers North Carolina study.

So, seven days post exposure I went to my local Internist and got baseline tested for all STDs including HIV (ELISA). All test results came back negative although I know only Chlamydia and Gonorrhea would be reliable after such a short period of time. I was told to come back to test for HIV (and the remaining STDs) at six weeks, three months, six months and one year. Well, the anxiety has gotten the better of me

I just saw an Infectious Disease doctor (HIV Specialist) in the urban city in which I live. At 32 days post exposure, I took the Aptima HIV-1 RNA Qualitative Assay and just received the results, which were negative. I believe this is the only FDA approved test for diagnostic screening. Although Ive read your comments stating The problem with HIV PCRs is the rate of false-positive results and cost as well as The test, however, is not meant to be used as a stand-alone test for the diagnosis of HIV-1 infection. A positive nucleic acid test should be viewed as a unconfirmed test result, indicating probable infection, and should be followed up later with traditional EIA antibody testing to confirm infection with the Human Immunodeficiency Virus.

Please correct me as this is purely supposition from what Im reading, but is the concern of using these tests for diagnostic purposes the high false positive rate, which would need to be confirmed with further testing; vice receiving a negative qualitative result after 28 daysor 32 days in my case, which some seem to deem conclusive? Or rather, it seems that negative test results for the Aptima HIV-1 RNA Qualitative Assay are potentially more reliable than positive results for diagnostic testing purposes, and Ive read on a few different websites that a negative test at 28 days is conclusive.

Can you kindly provide comment regarding this last paragraph? If nothing else, is this negative result an encouraging sign for me and/or are you able to assign an estimated percentage of the accuracy? The GEN-PROBE website cites a sensitivity confidence interval of 99.6%-100%.

Again, I thank you kindly for any response you can provide. If you would be so kind as to provide a link for donations in your response I will send one promptly.

All the best and continued good health and happiness. Signed, Aptimistaken???

Response from Dr. Frascino

Hi Aptimistaken,

Thanks for your kind comments! You are correct: the Aptima HIV-1 RNA Qualitative Assay is the only RNA PCR test approved by the FDA for HIV-diagnostic screening. You are also correct: the biggest problem with PCR assays is false-positive results and that is why a positive Aptima HIV-1 RNA test is considered a preliminary (unconfirmed) test result and requires a reactive (positive) "traditional" EIA (ELISA) HIV-antibody test before someone is given the diagnosis of HIV positive. False-negative results are not considered a significant problem with PCR assays. As for the exact window period for an Aptima test to be considered conclusive, yes, some Web sites and testing centers claim 28 days. I have not seen convincing scientific evidence that this is completely reliable. Confirming a definitive window period cutoff is extremely difficult, because there are a number of potentially confounding variables. Certainly we've learned from studying the natural history of HIV disease that those who have contracted the virus should have a positive HIV nucleic acid test by day 28. However, there are always unusual situations and rare complicating factors (such as technical or clerical errors) to consider. Nucleic acid testing is also much more difficult and costly to perform. All things considered, the HIV-antibody test taken outside the window period remains the gold standard for HIV diagnostic testing, at least for now.

PCR/nucleic acid testing can be very helpful in diagnosing acute HIV disease (ARS) within the window period. This is where I find the most appropriate use for this type of testing. I'll reprint below some information from the archives about the APTIMA test.

Donation information for The Robert James Frascino AIDS Foundation can be found on the foundation's Web site at www.concertedeffort.org. Thank you for your support. In return I'm sending my good-luck karma that you are now and will always be HIV free!

Be well. WOO-HOO on your negative APTIMA!

Dr. Bob

Another Aptima HIV PCR question Apr 19, 2010

Dr. Vegas here again. Thanks for the info re the Aptima PCR test. Could you answer another couple questions? When is the optimal time (to avoid false negatives) after exposure to do the test? I've been doing PCR's 4 weeks after exposure for both my occupational patients and those with sexual contacts. If the PCR is negative at whatever time is optimal what is the chance of the 3 month antibody test becoming positive? We do 3 month antibody tests on occupational exposures anyways but if the PCR is negative on the others is the 3 month antibody test still necessary?

Response from Dr. Frascino

Hi,

Unfortunately there is no temporal relationship regarding the likelihood of obtaining a false-positive HIV plasma RNA PCR. The problem relates to the test sensitivity and assay methods rather than to anomalies in the plasma.

There have been no controlled studies to scientifically answer your question concerning an undetectable PCR RNA at a specific time followed by a reactive anti-HIV antibody test at a later date. The anti-HIV antibody test at three months remains the gold standard. The Aptima PCR test is FDA approved for diagnosis, and other quantitative HIV PCR RNA tests and qualitative HIV PCR DNA tests have been used to identify infected patients during the acute retroviral syndrome. If a four-week Aptima PCR is undetectable, it would be extremely extremely unlikely a three-month HIV antibody test would be reactive in my experience.

Dr. Bob

Role of HIV PCR (APTIMA HIV-1 RNA QUALITATIVE ASSAY FDA APPROVED FOR DIAGNOSTIC USE) Apr 14, 2010

I am a family physician and first I wanted to commend your frank and frequently humorous answers to your readers questions. The appropriate use of humor when taking care of patients humanizes us as physicians. Continue your good work.

I am the medical director of a Las Vegas occupational/urgent care medicine clinic. We frequently see and manage blood borne pathogen exposures. (as well as the occasional patient who did something in Vegas that they want to stay in Vegas) Most are exceedingly low risk for HIV (needle sticks from diabetes syringes left in trash, etc) Some are slightly higher risk (HIV patients as source). Hepatitis B is a bigger concern but thanks to vaccine it doesn't present a huge problem.

In cases where the risk is slightly higher or the patient is exceptionally anxious I have been doing a 4 week HIV PCR. Our local Quest lab says this test is greater than 95% sensitive at 4 weeks. There are of course different PCR's. Judging from some of your answers it appears you don't recommend them. I agree that the 3 month HIV antibody test is definitive and seals the deal. Is there any role for the PCR's in my setting?

Response from Dr. Frascino

Hi,

Medical director of an urgent care facility in Vegas??? Now that must really be an entertaining position. I love Vegas and visit frequently. I'm always amazed at the often bizarre-appearing folks I see lumbering in and out of casinos on The Strip. I often have the urge to walk up to some of them and just say, "I demand an explanation." But, I digress . . . .

The problem with HIV PCRs is the rate of false-positive results and cost. Only one HIV-1 RNA PCR test is FDA approved for diagnostic screening (so far). It's the Gen-Probe APTIMA assay. (See below.)

Other HIV PCR tests are sometimes used to help diagnose someone who presents with a history of significant HIV exposure and is developing acute retroviral syndrome symptoms while still within the window period (defined as the first three months after exposure).

Hope that helps. Now can you help me with my craps game? I'm still a bit uncertain about all those onetime bets in the center of the table.

Be well. Thanks for appreciating my admittedly twisted sense of humor. Then again, you do live in Vegas, so . . . .

Dr. Bob

Approval of HIV-1 RNA qualitative assay for diagnostic use

The Food and Drug Administration (FDA) announced the approval, on October 5, 2006, of the APTIMA(r) HIV-1 RNA Qualitative Assay, manufactured by Gen-Probe Incorporated of San Diego, California, for use in clinical laboratories and public health facilities to detect primary (early) HIV-1 infection. The APTIMA® HIV-I RNA Qualitative Assay is an in vitro nucleic acid test (NAT) for the detection of human immunodeficiency virus (HIV-1) in human plasma intended for use as an aid in the diagnosis of HIV-I infection, including acute or primary infection, before the appearance of antibodies to HIV-1. Traditional detection and diagnosis of HIV-I infection is based on testing for anti-viral antibodies by enzyme immunoassay (EIA) with confirmation by supplemental antibody tests such as Western blot or immunofluorescence assays (IFA). Although sensitivity of HIV-1 antibody detection has increased in the last few years, a window period between infection and detectable serological markers still exists. Following a recent exposure to HIV-I, it may take several months for the antibody response to reach detectable levels, during which time, testing for antibodies to HIV-I, including the use of rapid antibody tests, will not indicate true infection status. The newly approved test may provide earlier diagnosis of infection because it detects nucleic acid of the human immunodeficiency virus (HIV-1) in human plasma, rather than the antibody response to the virus. Presence of HIV-I RNA in the plasma of patients without antibodies to HIV-I is indicative of acute or primary HIV-1 infection. The test, however, is not meant to be used as a stand-alone test for the diagnosis of HIV-1 infection. A positive nucleic acid test should be viewed as a unconfirmed test result, indicating probable infection, and should be followed up later with traditional EIA antibody testing to confirm infection with the Human Immunodeficiency Virus. In addition, the APTIMA HIV-1 RNA Qualitative Assay may be used as an additional test to confirm HIV-I infection in an individual whose specimen is repeatedly reactive for HIV-1 antibodies. This is important because the Western blot can, in some instances, be difficult to interpret and may not always provide a conclusive result. The APTIMA test can be used instead of the traditional Western blot test or IFA for confirmation of HIV-1 infection when the screening test result for HIV-1 antibodies is positive. The sensitivity of the APTIMA(r) HIV-1 RNA Qualitative Assay is comparable to that of FDA approved viral load assays that measure the amount of HIV-1 virus circulating in the blood of patients with established HIV-1 infection to monitor the treatment and progression of AIDS. Unlike the viral load tests, however, the APTIMA test has been approved for the diagnosis of primary HIV-1 infection, as well as for confirming HIV-1 infection when tests for antibodies to HIV-1 are positive. The product labeling for this test will be available soon on the list of FDA Licensed/Approved HIV, HTLV and Hepatitis Tests on the FDA web site. Richard Klein Office of Special Health Issues Food and Drug Administration



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