What Is The Accuracy Of An Hiv Combo Test At

Posted on Sun, 20 Sep 2020

Sun, 20 Sep 2020 Answered on

Last reviewed on

Question : What is the accuracy of an hiv combo test At 3.5 months and 4 months post exposure .

I tested non reactive but I have some symtoms like fatigue .

Also what’s the probability for labs to mix up samples while testing . Please advise . Thanks

Answered by Dr. Sankaranantham Murugan (49 minutes later)

Brief Answer:
Your symptoms are not related to HIV infection

Detailed Answer:
Hi,
Welcome to Ask A Doctor service.
Thanks for posting your query.
Window period for HIV antibody test is 6-8 weeks. HIV 4th generation Combo test is highly reliable to the extent of more than 99 % 12 weeks after the exposure. So your HIV negative report 3 months after the exposure is very much conclusive and confirmatory. Your fatigue symptoms are unlikely to be due to HIV infection.
Clerical laboratory error in mixing up and labelling is extremely rare as they are experienced and used to follow a routine protocol.
Dr S Murugan

Above answer was peer-reviewed by : Dr. Vaishalee Punj

Follow up: Dr. Sankaranantham Murugan (36 minutes later)

Thanks dr XXXXXXX for your quick response .

Just to elaborate a bit :

I did the first HIV combo test from metropolis labs . I also did other routine tests . However the clconic told me that hiv report isn’t ready and it is being rechcked . I got extremely worried and then I waited for an hour and they sent me the reports , it was NON reactive .

Since I still wasn’t sure I did another test form another lab this time . However my father did some other tests as well on the same day and now my worry is what if they mixed my samples by mistake with his .

My result was non reactive . But I’m getting swollen nodes , I feel small one s in m neck . However when i showed my gp he says he can’t find any nodes .

My risk was oral sex exposure with another Male .
I have NOT had any form of anal or vaginal sex ever .

I am getting constant anxiety about this and I don’t know how to resolve it . My daily activities are getting affected .

Also when u say 99 percent accurate at 3 months , one percent means there is still some chance of infections ?

Have you even seen a 4 month combo test turn positive later ?

Please advise , I am very anxious and stressed . Thanks doctor

Answered by Dr. Sankaranantham Murugan (2 hours later)

Brief Answer:
Cervical lymph adenitis can occur conditions other than HIV.

Detailed Answer:
Hi,
Welcome back.
Oral sex carries a low risk for HIV infection as per CDC, XXXXXXX United States.
I cannot give guarantee for any laboratory and their staffs. Presence of lymph node enlargement can best be judged by the physician.
Due to your anxiety and fear, it could be assumed by you.
Through oral sex one can get cervical lymph adenitis due to bacterial infection even in the absence of HIV infection. If it is so consult a ENT specialist and get well soon.
I hadn't come across anybody reactive for HIV 4 months after exposure, while it was nonreactive at 3 months test with 4th generation HIV Combo test. Moreover HIV Combo test detects both antigen and antibody for HIV infection. So it becomes highly reliable to the extent of more than 99 %.
Dr S Murugan

Above answer was peer-reviewed by : Dr. Prasad

Follow up: Dr. Sankaranantham Murugan (52 minutes later)

Hi doctor , thanks for your response .

Do you recommend any firther testing ? I have tested from two different labs at 3 months and 3.5 months .

Also the perosn I had oral sex with showed me his reports and he had tested negative .

I have consulted you multiple time’s in the past too as I have full faith in your advice and consultation .

Do you recommend another combo test ?

My first blood test was from metropolis and second was from a local lab .

Also my esr was 2 and c reactive Protien was 0.4.

If it was hiv would esr and c reactive Protien be high ?

I mean is higher esr seen in perosn with hiv ?

Finally , sinxe I am a bisexual male , though not very sexual active ( I haven’t had anal or vagina sex) .

Would you recommend the use of prep ?
What would its side effects be ? Please advise . Thanks

Answered by Dr. Sankaranantham Murugan (26 minutes later)

Brief Answer:
No further HIV test necessary for you.

Detailed Answer:
Hi,
Welcome back
I don't recommend you further testing for HIV.
ESR, CRP will be raised in HIV only in advance disease not in early infection.
What is your age, are you married or not? Regarding PrEP, I will advise after having the above details.
Dr S Murugan

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Sankaranantham Murugan (1 hour later)

Hi doctor ,

I am 29 years old . I am not married and don’t plan to marry anytime soon.

I have severe anxiety about hiv and this has affcedted my work and life in general .

I have tested from two different labs dofferent labs . I assume that two labs wouldn’t be wrong , but I am still Getting worried at times .

I don’t plan to indulge in anal or vaginal sex, however now oral sex also worries me . Please advise . Thanks

Answered by Dr. Sankaranantham Murugan (9 hours later)

Brief Answer:
Stick to safe sex always

Detailed Answer:
Hi,
Welcome back.
My advice for you, is.. Get married soon.
If not possible, stick to safe sex always. Condoms for Oral sex are also available.
If this is also impossible for you, PrEP is the alternative for.
You. This you have to take regularly and daily as long as you are Sexually active. PrEP has less side effects and most of the people are tolerating well. But it is always better to take the same under the supervision of a physician expert in HIV medicine.
Dr S Murugan

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Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar