Public health significance
Still one of the most consequential results a PHL signs. The algorithm is the product, not the screen.
Specimen types
Serum, plasma
Method
Fourth-generation immunoassay
CLIA / validation
High complexity or moderate, depending on the platform. Differentiation and NAAT are part of the quality system.
Interpretation
Reactive / Nonreactive. A reactive screen is not a diagnosis and should not go to ELR alone.
Reflex / referral
HIV-1/2 differentiation, then NAAT if discordant, per CDC algorithm.
Quality control
Kit controls. External QC at a frequency matching volume and kit stability.
Reportability
Confirmed HIV is reportable. Screens are not cases.
HL7 / ELR
LOINC 56888-1 for the combo. Confirmatory assays get their own OBX rows.
Sources
CDC HIV laboratory testing algorithm.