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Author Topic: Can Quick Tests be inaccurate?  (Read 1256 times)

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Offline Loa111

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Can Quick Tests be inaccurate?
« on: June 24, 2020, 06:21:14 am »
I always wondered about this. About 5 years ago I had a Quick Test where my finger was pricked, and it showed I was negative, this is when I was living over in Thailand, and I felt great relief at the time.

Of course a couple of years later I started to get sick with various OI's and ended up getting my DX and finding out that I am positive.

I've always wondered if the quick test I did approx 5 years ago was a false negative?

I'm assuming, since I ended up with an advanced Dx that I was positive for up to 10 years before Dx, so my ID Doc says. I explained about this quick test, and he said it was probably a false negative and didn't rate the accuracy of a Quick Test in Thailand

It something I often think aback on, and always wondered what the odds of a false negative are?

Offline Jim Allen

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Re: Can Quick Tests be inaccurate?
« Reply #1 on: June 24, 2020, 06:39:36 am »
Based on test/lab results, outside of picking up on a recent infection, there is no way to know how long you have been living with HIV. Some people progress very fast within a brief few years to AIDS others takes decades.

As for the test, depends on what test. If it's was an approved and recognised test, not one of these fakes or dogy ones on the market and taken correctly and after the window period, the odds of a false negative are minute to non-existent.

I do understand the wondering or questioning past results etc, I've done that myself for a few years, it got so back it used to even keep me up at night and I had a reoccurring dream at some stage, that was until I concluded or accepted, it's best to let it go and stick to the facts I have.
« Last Edit: June 24, 2020, 06:51:33 am by Jim Allen »
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Offline Valentines19

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Re: Can Quick Tests be inaccurate?
« Reply #2 on: June 25, 2020, 08:38:15 pm »
Iíve been wondering the same thing recently. How accurate are these quick tests?
About 5 months before my diagnosis, I took an Oraquick Test.. purely out of curiosity and because I hadnít been tested in a while. The result was negative. 5 months later I had a CD4 count of 55 and VL of nearly 1 million.

Immediately after the diagnosis, i carefully read the directions again and and did two more oraquick tests (I was in the deep denial stage) they both came in negative. I read somewhere that in advanced infections, there are much less antibodies so Iím assuming the tests had a hard time registering an infection.  Does that sound about right? Anyone else have a similar experience?

Offline Jim Allen

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Re: Can Quick Tests be inaccurate?
« Reply #3 on: June 26, 2020, 01:52:07 am »
Hiya,

The tests generally would pick up on antibodies at advanced infection, AIDS stage. They are highly accurate for screening but as with everything not perfect.

Jim
« Last Edit: June 26, 2020, 01:56:33 am by Jim Allen »
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Offline jayorangevii

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Re: Can Quick Tests be inaccurate?
« Reply #4 on: September 02, 2020, 11:38:24 am »
Iíve been wondering the same thing recently. How accurate are these quick tests?
About 5 months before my diagnosis, I took an Oraquick Test.. purely out of curiosity and because I hadnít been tested in a while. The result was negative. 5 months later I had a CD4 count of 55 and VL of nearly 1 million.

Immediately after the diagnosis, i carefully read the directions again and and did two more oraquick tests (I was in the deep denial stage) they both came in negative. I read somewhere that in advanced infections, there are much less antibodies so Iím assuming the tests had a hard time registering an infection.  Does that sound about right? Anyone else have a similar experience?


I just want to add that I had been infected in April 2020 and  after 3 months I had performed the ora quick test and it gave me two false negatives as well.  A week later I tested poz for HIV. So to yojr point I have experienced that as well.
Serving Realness---JAY

Offline TGun

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Re: Can Quick Tests be inaccurate?
« Reply #5 on: September 09, 2020, 01:50:22 pm »
oraquick works,, i can personally validate its effectiveness.  i believe it saved my life and others around me.  i have lived symptom free and a healthy life due to it being readily available.

Offline jayorangevii

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Re: Can Quick Tests be inaccurate?
« Reply #6 on: September 09, 2020, 03:27:14 pm »
I think oraquick should be reinforced with a blood test, had i not had a blood test after my two false negatives from oraquick (false negatives after a 3 month waiting period from infection) then I would have continued to live life like normal. These tests should be a stepping stone to knowing your status not a conclusive result
Serving Realness---JAY

Offline Jim Allen

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Re: Can Quick Tests be inaccurate?
« Reply #7 on: September 09, 2020, 04:45:57 pm »
Approved rapid tests used correctly are highly accurate and provide low barrier opportunities to screen more people than conventional lab testing does.

I think it's been a key tool in this epidemic that's still underutilized in community settings.

Jim
« Last Edit: September 09, 2020, 04:53:16 pm by Jim Allen »
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Offline jayorangevii

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Re: Can Quick Tests be inaccurate?
« Reply #8 on: September 09, 2020, 07:40:40 pm »
Not refuting that its a key tool. Merely stating the fact that the accuracy is not 100% and isn't an absolute and should be followed up when able to and appropriate. Check out this article specifically regarding  oral fluid vs finger stick blood and serum. Its just one article but its worth noting.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906506/
Serving Realness---JAY

Offline Jim Allen

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Re: Can Quick Tests be inaccurate?
« Reply #9 on: September 09, 2020, 08:31:19 pm »
Not refuting that its a key tool. Merely stating the fact that the accuracy is not 100% and isn't an absolute and should be followed up when able to and appropriate. Check out this article specifically regarding  oral fluid vs finger stick blood and serum. Its just one article but its worth noting.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906506/

No conflict here as far as I am aware. I was just generally weighing in that approved rapid tests used correctly have shown to be highly accurate and my own thoughts that they provide low barrier opportunities to screen more people than conventional lab testing.

Quote
should be followed up when able to and appropriate.

Instressting, considering no test including blood tests will be 100% absolute, appropriate, my own thought would be anyone who is sexually active where possible should be routinely screening for STI & HIV regardless of past results.

Generation 3

Pilcher CD et al. Performance of Rapid Point-of-Care and Laboratory Tests for Acute and Established HIV Infection in San Francisco. PLOS ONE, 2013.

Branson BM State of the art for diagnosis of HIV infection. Clin Infect Dis 45:S221-225, 2007

Coombs RW Clinical laboratory diagnosis of HIV-1 and use of viral RNA to monitor infection. In Holmes KK (editor), Sexually Transmitted Diseases. New York: McGraw-Hill, 2008

Maldarelli F Diagnosis of Human Immunodeficiency Virus infection. In Mandell, Douglas and Bennettís Principles and Practice of Infectious Diseases (sixth edition). Philadelphia: Elsevier Churchill Livingstone, 2004

Parry JV et al. Towards error-free HIV diagnosis: guidelines on laboratory practice. Comm Dis Pub Health 6:334-350, 2003

3rd gen testing accuracy Perry KR et al. Improvement in the performance of HIV screening kits. Transfus Med 18:228-240, 2008

Generation 3 & 4

http://i-base.info/guides/testing/test-accuracy-results-and-further-testing

http://i-base.info/guides/testing/appendix-1-different-types-of-hiv-test

2015
Taylor, D., Durigon, M., Davis, H., Archibald, C., Konrad, B., Coombs, D., et al. (2015). Probability of a false-negative HIV antibody test result during the window period: a tool for pre- and post-test counselling. Int. J. STD AIDS 26, 215Ė224. doi: 10.1177/0956462414542987

Patients typically want accurate test results as soon as possible while clinicians prefer to wait until the probability of a false-negative is virtually nil. This review summarizes the median window periods for third-generation antibody and fourth-generation HIV tests and provides the probability of a false-negative result for various days post-exposure. Data were extracted from published seroconversion panels. The median (interquartile range) window period for third-generation tests was 22 days (19-25) and 18 days (16-24) for fourth-generation tests. The probability of a false-negative result is 0.01 at 80 days' post-exposure for third-generation tests and at 42 days for fourth-generation tests.

Generation 4

2012
Rosenberg NE, Kamanga G, Phiri S, et al. Detection of acute HIV infection: a field evaluation of the determine(R) HIV-1/2 Ag/Ab combo test. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3318673/

Results. Of the participants 838 were HIV negative, 163 had established HIV infection, and 8 had acute HIV infection. For detecting acute HIV infection, the antigen portion had a sensitivity of 0.000 and a specificity of 0.983. For detecting established HIV infection, the antibody portion had a sensitivity of 0.994 and a specificity of 0.992.

2011
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222669/
Conclusions. Combo RT displayed excellent performance for detecting established HIV infection and poor performance for detecting acute HIV infection. In this setting, Combo RT is no more useful than current algorithms.

In total, 953 people underwent HIV testing. HIV antibody (Ab) prevalence was 1.8% (17/953). Four false positive rapid tests were identified: two antibody and two p24 antigen (Ag) reactions. Of participants diagnosed as HIV Ab positive, 2/17 (12%) were recent seroconverters based on clinical history and HIV antibody avidity test results. However, none of these were detected by the p24 antigen component of the rapid test kit. There were no other true positive p24 Ag tests.

https://www.cdc.gov/hiv/testing/clinical/index.html
2018
CDC recently published research findings that estimate the window period for 20 U.S. Food and Drug Administration (FDA)-approved HIV tests. The study showed that laboratory testing using antigen/antibody tests detects HIV infection sooner than other available tests that detect only antibodies. If a person gets a laboratory-based antigen/antibody test on blood plasma less than 45 days after a possible HIV exposure and the result is negative, follow-up testing can begin 45 days after the possible HIV exposure. For all other tests, CDC recommends testing again at least 90 days after exposure to be sure that a negative test result is accurate.

Bentsen C Performance evaluation of the Bio-Rad Laboratories GS HIV Combo Ag/Ab EIA, a 4th generation HIV assay for the simultaneous detection of HIV p24 antigen and antibodies to HIV-1 (groups M and O) and HIV-2 in human serum or plasma. Journal of Clinical Virology, S57-S61, 2011

Nick S Sensitivities of CE-Marked HIV, HCV, and HBsAg Assays. Journal of Medical Virology, S59-S64, 2007

Eshelman S Detection of Individuals With Acute HIV-1 Infection Using the ARCHITECT HIV Ag/Ab Combo Assay. Journal of Acquired Immune Deficiency Syndromes, 121-4, 2009

Speers D et al. Combination assay detecting both Human Immunodeficiency Virus (HIV) p24 antigen and anti-HIV antibodies opens a second diagnostic window. J Clin Microbiol 43:5397-5399, 2005

Ly TD et al. Evaluation of the sensitivity and specificity of six HIV combined p24 antigen and antibody assays. J Virol Methods 122:185-94, 2004

2020 http://www.bhiva.org/ https://www.bhiva.org/file/5dfceab350819/HIV-Testing-Guidelines.pdf
Recommendations (Grade 1A)

ē Clinic policies and patient information regarding the HIV test window period should be based on 99th percentile estimates; where a test is undertaken sooner than this time interval, window period data should be used to counsel patients as to the likelihood of a false-negative result.

ē Fourth-generation laboratory tests reliably exclude HIV by 45 days post-exposure, and this should be the window period applied when utilising these tests.

ē Third-generation laboratory tests reliably exclude HIV by 2 months post-exposure, and this should be the window period applied when utilising these tests.

ē POCTs reliably exclude HIV by 90 days post-exposure, and this should be the window period applied when utilising these tests.

2015 WHO http://apps.who.int/iris/bitstream/handle/10665/179870/9789241508926_eng.pdf;jsessionid=1F192FECF734A0DE7E2520864984AE63?sequence=1
In many settings post-test counselling messages recommend that all people who have a
non-reactive (HIV-negative) test result should return for retesting to rule out acute
infection that is too early for the test to detect. However, retesting is needed only for HIV-negative individuals who report recent or ongoing risk of exposure. For most people who test HIV-negative, additional retesting to rule out being in the window period is not necessary and may waste resources.

« Last Edit: September 09, 2020, 08:48:15 pm by Jim Allen »
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