W/o RIBA, is there ever a false pos antibody test?

[mark560]

I donated blood, as i have done for years. Came back a month ago antibody HCV reactive, but NAT was NR.
I think i may have had a false positive.
My question
From what i am reading, i think the only way to rule out a false positive HCV test is to do a RIBA. Which, i guess we don't do in the US anymore.
If Anti HCV misread another antibody, it will always misread the antibody as HCV.
Therefore, i will always test HCV antibody positive.
I a, concerned i will not be able to get life insurance if this is the case, since the test to clear me is RIBA, and i cannot get a RIBA test

[mark560]

Thanks for the advice. I am waiting on test results of the RNA. Wonder how long it will be before we get RIBA back

[Idyllic]

You are right. According the circumstances you outline a negative RIBA result is required for re-entry into the blood donor pool.

U.S. FDA guidance (a document covering these issues in May 2010)
http://www.fda.gov/downloads/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guidances/Blood/UCM210270.pdf

The "Blood Bank Guy" explains it in a manner easier for me to understand so kudos to you for figuring all this out. The confirmatory test used whenever a reactive EIA/ChLIA is seen is known as RIBA ("recombinant immunoblot assay").

http://bbguy.blogspot.com/2011/01/hepatitis-c-testing.html

1. Anti-HCV EIA repeat reactive, RIBA any result, HCV NAT reactive
    FDA does NOT allow these donors to ever donate again. They are "permanently deferred."

2. Anti-HCV EIA repeat reactive, RIBA positive, HCV NAT reactive OR nonreactive

    FDA does NOT allow these donors to ever donate again. They are "permanently deferred." Note that most donors in this situation will be NAT-reactive, but as many as 10-30% will NOT have a reactive HCV NAT.


3. Anti-HCV EIA repeat reactive, RIBA negative or indeterminate, HCV NAT nonreactive

    These donors are "indefinitely deferred", but are eligible for re-entry consideration after SIX MONTHS from the donation date

4. Anti-HCV EIA nonreactive, HCV NAT reactive

    These donors are "indefinitely deferred", but are eligible for re-entry consideration after SIX MONTHS from the donation date

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The Labcorp Test Menu says this about RIBA. (I am not sure if the FDA considers this a viable substitute for the RIBA):

Due to the manufacturer's nationwide stock shortage of sole-source HCV RIBA testing material, effective March 19, 2012, LabCorp suspended all HCV RIBA testing. Clients seeking supplemental testing following a reported positive HCV antibody screen may consider ordering Hepatitis C Virus (HCV) Antibody With Reflex for Antibody Verification (144065)

https://www.labcorp.com/wps/portal/!ut/p/c0/04_SB8K8xLLM9MSSzPy8xBz9CP3I1JT8YquyzNTykNTiEqdKEOlXmpuUWqQfDlJeguBHGpoYmhhY6Bfk5joCADezVwk!/
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QUEST labs do not say the test is unavailable. Here is the QUEST link:
http://www.questdiagnostics.com/testcenter/testguide.action?dc=CF_ViralHepatitis
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I see what you mean about life insurance. Will an undected HCV PCR suffice? There are some circumstances where a doctor's letter and the HCV PCR help with issues such as yours. You might want to see what your options are prior to being declined.

Best of luck