Paper I — 2022 July (Supplementary) (2019 Scheme) — Q12
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Paper I
2022 July (Supplementary) (2019 Scheme) · 100 marks · 180 min
Question
NACO strategies for HIV testing
Q124 marksShort Answers
Answer
NACO (National AIDS Control Organisation) strategies for HIV testing
A structured, stringent testing algorithm ensures diagnostic accuracy, based on the principle that a reactive result must be confirmed using a sequence of different test kits, based on different antigen preparations or test principles, before a definitive result is reported.
Strategy I — used for blood/organ/tissue donor screening: a single ELISA/rapid test is sufficient to determine transfusion/donation safety (high sensitivity prioritized, since a false negative — transfusion-transmitted HIV — is far worse than a false positive requiring donor deferral).
Strategy II — used for surveillance (estimating population HIV prevalence, e.g., unlinked anonymous antenatal/STD clinic surveillance): two tests are used; a sample reactive on both is considered positive for surveillance purposes.
Strategy III — used for individual diagnosis: three different tests/kits, using different antigens/principles, are used serially (testing proceeds to the next kit only if the previous one is reactive); a sample must be reactive on all three before HIV infection is confirmed and reported to the individual — minimizing the risk of a false-positive diagnosis, given its serious psychosocial/medical consequences.
Testing infrastructure: NACO operates a network of Integrated Counselling and Testing Centres (ICTCs) offering free, confidential testing with pre- and post-test counselling; PPTCT (Prevention of Parent-to-Child Transmission) services target antenatal screening.
Confirmatory principle: reactive point-of-care/field results are always confirmed via the full Strategy III algorithm at a linked laboratory before a definitive diagnosis is communicated.
