[Question #4078] Siemens Centaur DUO HIV Test

33 months ago
Hi Doctors,

Unfortunately, I find myself back on the site. I was starting to feel better regarding my past exposure, until I learned that LabCorp was using the Siemens Centaur DUO HIV test. I researched the sensitivity of this test, and it doesn't seem to stack up to the competitors (ie. Elecsys combi PT). Many studies are showing that the Centaur only has a sensitivity of 98.36% while the others are much closer, or at the 100% mark. 

I have tested with the Siemens Centaur DUO at 6 weeks, 8 weeks, 12 weeks, and 18 weeks.

1. What is your opinion on the  test I have taken? Have you heard any feedback on this specific testing platform?

2. Do you recommend certain 4th generation lab based tests over others?

3. Am I missing something when looking at this data, or am I correct in my train of thought?
Edward W. Hook M.D.
Edward W. Hook M.D.
33 months ago
Welcome back to the Forum.  I'm sorry that your low risk exposure continues to worry you.  There is no meaningful statistical difference between the performance of the Siemens assay and other antigen/antibody tests for HIV.  Further, when persons are missed they tend to be missed and repeated testing further reduces any possible chance of missing an infected person.  Your test results are conclusive and should be believed.  Further testing related to your past exposure is a waste of time and resources. 

1. What is your opinion on the  test I have taken? Have you heard any feedback on this specific testing platform?
Please see above.  Siemens is a highly respected, reliable company whose assay has passed FDA clearance.

2. Do you recommend certain 4th generation lab based tests over others?
No

3. Am I missing something when looking at this data, or am I correct in my train of thought?
You are overthinking this.  Published minor differences in the performance of tests becomes virtually irrelevant with repeat testing and is of no meaningful consequence for the many, many people who are tested with this assay. 

I hope my further comments will allow you to move on without concern.  EWH
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33 months ago
Thanks for the response. I talked to my PCP today. I explained the situation and he said that he wouldn't have recommended testing in the first place. Do you agree with that? Also, if I were to take a RNA and antibody test, would that make my results even more definitive?
Edward W. Hook M.D.
Edward W. Hook M.D.
33 months ago
I agree with your PCP that your exposure was very, very low risk but you did acknowledge a small amount of unprotected sex. 

An RNA PCr has a small chance of being falsely positve. 

as I've already told you, I consider your test results definitive and that you are overthinking this.  EWH
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33 months ago
Thank you. Also, in the study I read, it referred to this particular test "failing to detect diluted antigen/antibody", and that's what made me worry. What exactly is diluted antigen/antibody, and why would it fail to detect this in certain subtypes?
Edward W. Hook M.D.
Edward W. Hook M.D.
33 months ago
I am not sure what study you have read.  If you wish to provide a link I will take a look.  Typically tests are not performed on serum or plasma which has diluted.  The dilution process can reduce the concentration of antibody present.  The Siemens test is typically performed on undiluted antibody.  EWH
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33 months ago
Here is the link to the study. I may be misinterpreting the date. Your feedback is much appreciated 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3562432/
Edward W. Hook M.D.
Edward W. Hook M.D.
33 months ago
I looked at this 5 year old article.  There are tables which included evaluation of diluted antigen or antibody levels, something that is not done when the test is used as manufacturer's instructions are followed.  In general this assay compares quite favorably with other assays that are available.  There is NOTHING here that should concern you. Quite the contrary, this study validates the high performance standards and validity of test results using this assay.  You do not have HIV.  Believe it!

With this, this thread will be closed.  Further anxiety-driven or repetitive posts may be deleted without further comment.  I urge you to move forward without concern.  EWH
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