National strategies and algorithms for HIV

NACO algorithm for HIV/AIDS

1. National Strategies and Algorithms For HIV Testing Dr. Arkadeb Kar Post-graduate Trainee Calcutta National Medical College And Hospital

2. A testing strategy refers to selecting the best type of test, or more than one type of test, for identifying and confirming HIV infection in a particular testing situation like: Blood /Organ donation safety Surveillance Diagnosis

3. Involve a logical sequence of performing two or more tests, one after the other (serial) or simultaneously (parallel) to arrive at a conclusion on the HIV status of a person being tested. A testing algorithm refers to the combination and sequence of specific tests that are used to fulfil the testing strategy . India's strategy is based on serial testing and includes repeat testing of initially reactive sample.

4. Objectives Transfusion and transplant safety Diagnosis of HIV infection in symptomatic and asymptomatic individuals Prevention of parent to child transmission For Post-Exposure Prophylaxis (PEP) Epidemiological surveillance using unlinked anonymous HIV testing Research

5. Commonly used tests Enzyme Linked Immunosorbent Assay (ELISA) Rapid tests Immunoconcentration / Dot Blot assay (vertical flow) Agglutination assay Immunochromatographic assay (lateral flow) Dipstick and comb assay based on Enzyme Immune Assay (EIA) Confirmatory tests with high specificity, like WBs and line immunoassays, are used in problem cases, e.g., in cases of indeterminate/discordant result of ELISA /Rapid tests.

6. Testing policies to be considered: Testing should be part of the overall comprehensive prevention programme . Testing should be technically sound and appropriate. Testing procedures must be field appropriate. Testing procedures must be cost effective. Laboratory procedures must be monitored to ensure quality .

7. Strategy 1 (for blood transfusion/transplant safety) The test used in strategy 1 must have high sensitivity. The unit of blood that tests reactive (positive) is discarded. If the donor is to be notified of his result, based on his prior consent , it becomes a matter of diagnosis (in which case strategies II & III must be used after proper counselling) and the donor should be referred to an ICTC for the confirmation of the result

8. Strategy 2 A (used in sentinel surveillance) This type of HIV testing is anonymous and unlinked. It is reported positive only if the second ELISA/rapid test also gives a reactive report like the first test.

9. Strategy 2 B (used for diagnosis in symptomatic patients) where the physician indicates that the patient is suffering from clinical AIDS like symptoms , the HIV status of the patient can be confirmed as positive on the basis of two reactive test results . In case a specimen is reactive with the first test kit and non reactive with the second test kit, the specimen is subjected to a third tiebreaker test. If the third test is reactive, the specimen is reported as indeterminate and follow up testing is undertaken after 2 to 4 weeks . In case the third tiebreaker test is non-reactive, the specimen is reported negative . Counselling, informed consent, and confidentiality are a must in all these cases

10. Strategy 3 (used for diagnosis in asymptomatic patients) If the specimen gives a reactive result with two E/R and non-reactive result with the third assay, it is reported as “indeterminate” and the patient is called again for repeat testing after 2-4 weeks The test utilized for the first screening should be the one with the highest sensitivity and those used for the second and third tests are those with the highest specificity This strategy is used for the diagnosis of HIV infection in asymptomatic individuals at ICTCs and PPTCT centres . Testing should be repeated on a second specimen taken after 14-28 days. In case the serological results continue to be indeterminate, then the specimen is to be subjected to a WB/PCR if facilities are available or refer to the NRL for further testing.