Alternative flowchart for HIV screening and sequential confirmation (accessible version)
Updated 25 May 2022
Applies to England
© Crown copyright 2022
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/infectious-diseases-in-pregnancy-screening-programme-laboratory-handbook/alternative-flowchart-for-hiv-screening-and-sequential-confirmation-accessible-version
For reporting comments please use the results table and reporting comments for HIV.
1. Perform HIV infection screening with a combined antigen/antibody (Ag/Ab) assay. Is HIV Ag/Ab detected or equivocal?
If no, report as HIV Ag/Ab not detected. End of laboratory pathway.
If yes, perform a second Ag/Ab assay. Go to step 2.
2. Is HIV Ag/Ab detected or equivocal in second Ag/Ab assay?
If no, inconclusive result. Repeat serology in 2 weeks and request an EDTA sample for HIV viral load. Go to step 4.
If yes, complete confirmation with typing assay. Go to step 3.
3. Is HIV infection confirmed in the typing assay?
If yes, depending on the result of the typing assay, either:
a) report result as HIV-1 detected
or
b) if HIV-2 detected or both HIV-1 and HIV-2 detected, refer to reference laboratory that undertakes HIV-2 serology and HIV-2 RNA testing for confirmation. If confirmed, report either HIV-2 infection or HIV-1 and HIV-2 infection as appropriate. End of laboratory pathway.
If no, possible early infection. Repeat serology in 2 weeks and request an EDTA sample for HIV viral load. Go to step 5.
4. Are Ag/Ab assays and HIV-1 RNA all detected?
If yes, complete confirmation with typing assay. End of laboratory pathway.
If no, if serology is unchanged and HIV-1 RNA not detected, or neither serology nor HIV-1 RNA detected, report no evidence of HIV infection (false positive). End of laboratory pathway.
5. Is serology unchanged, or typing assay detected, and HIV-1 RNA detected?
If yes, report HIV-1 infection confirmed. End of laboratory pathway.
If no, report as no evidence of HIV infection (false positive). End of laboratory pathway.