PMTCT Prevention of Mother-to-Child Transmission of HIV

1. PMTCTPrevention of Mother-to-Child Transmission of HIV Module 5: HIV TESTING 1

2. Learning Objectives • Describe the benefits of the HIV rapid tests and DNA PCR. • Describe the Zambian testing algorithm • Demonstrate skills in HIV testing including DBS collection 2

3. Learning Objectives • Describe how to interpret the patient’s HIV tests results accurately. • Describe the quality assurance procedures • Describe the required recording-keeping tools and data reporting requirements relevant to HIV testing. 3

4. HIV testing and its benefits All testing follows the same basic steps: • Sample is obtained. Most often, a blood sample is taken from a person's fingertip or arm. • Sample is processed. This can be done on site—for example, at the ANC clinic or in labour and delivery for rapid tests—or in a laboratory. • Healthcare worker obtains results. 4

5. HIV testing and its benefits cont.. • Healthcare worker provides results to the patient during post-test counselling. • In an adult, a positive HIV antibody test result means that the person is infected with HIV whereas in an infant below 12 months a positive test may arise from circulating maternal antibodies. • A negative result usually means that the person is not infected with HIV. • In rare instances, a person with a negative result may be in the “window period 5

6. Testing for HIV • Blood test detecting either • antibodies to HIV Infection or • HIV antigens 6

7. Antibody tests • When HIV enters the body, the body responds by making a protein called an antibody that can be detected by Rapid HIV test. 7

8. Rapid testing All rapid tests share the following characteristics: • Highly accurate when performed correctly • Usually performed on whole blood (either taken as a finger prick or drawn as a sample); occasionally saliva is collected by using a swab • Do not require special laboratory equipment or refrigeration • Results are ready within 30 minutes • Tests can be done on a single specimen • Clinic staff can be trained to perform the tests 8

9. Benefits of rapid testing include: • Blood samples can be analysed in the clinic. • Same-day results are more convenient for the patient. • Providers can avoid missed opportunities when there is no follow-up care. • Pregnant women who are HIV-positive can be informed immediately about MTCT interventions and possible treatment options. • Providers do not need to track down test results from an outside laboratory. • There is less risk of specimen mix-up or misplacement 9

10. Viral tests or assays • Virologic testing or assays directly detect the presence of HIV in blood specimens as opposed to the antibody test, which detects the presence of antibody as an indirect measure of the presence of virus. Viral assays/tests must be done by trained personnel in the laboratory. 10

11. Viral tests or assays cont.. There are two main types of tests: • p24 antigen tests measure one of the proteins found in HIV (antigen).This is currently not available in Zambia • PCR (polymerase chain reaction) tests detect viral DNA or RNA: • DNA PCR detects the presence of the virus in the blood and is used for diagnosis of the infant less then18 months. • RNA PCR detects and measures the amount of virus in blood (It is used to measure viral load). 11

12. Diagnostic testing of infant and young children exposed to HIV • Antibody testing is not appropriate for diagnosis in infants because they have circulating HIV antibodies acquired from the mother • PCR testing is able to identify the virus in the infants’ blood with accuracy from one month of age. • If a child exposed to HIV develops signs or symptoms of HIV infection, early diagnosis and intervention is critical 12

13. HIV antibody testing of infants and young children less than 18 months • Early diagnosis of infection in these infants is difficult, and is further complicated by breastfeeding. • Since maternal antibodies cross the placenta, all infants born to mothers infected with HIV will test antibody positive, irrespective of their own infection status. 13

14. HIV antibody testing of infants and young children less than 18 months • Because maternal antibodies persist, antibody testing prior to 18 months cannot provide a reliable diagnosis of infant infection status, especially when the child is breastfeeding. • In Zambia, initial antibody testing is recommended at12 and 18 months ( 6 weeks after cessation of breastfeeding) 14

15. For children who are not breastfeeding or where breastfeeding cessation occurred at least 3 months previously • A negative HIV antibody test result for a child 18 months or older indicates that the child is not HIV-positive. • A positive HIV antibody test at 18 months or older indicates the child is infected with HIV. • OR • A negative HIV antibody test result for a child age 12–18 months indicates that the child is not infected with HIV. • A positive HIV antibody test at 12-18 months of age indicates that the child may have antibodies from the mother and the test should be repeated at 18 months. 15

16. For children who are breastfeeding: • If the test is negative at 18 months of age or older and the infant was breastfeeding in the last 6 weeks, the antibody test should be repeated 6 weeks after complete cessation of breastfeeding. • A positive HIV antibody test result at 18 months indicates that the child is HIV-infected. 16

17. Discussion • Discuss the table of HIV diagnosis in exposed infants less than 18 months 17

18. HIV viral assays in infants • Viral assays that detect HIV in the infant's blood, such as the DNA or RNA PCR test, may be used to diagnose HIV infection in infants at a younger age than antibody testing. • Early diagnosis of HIV allows the provider to promptly initiate counselling about methods of infant feeding and facilitates early clinical care for the infant who is HIV-infected. • They are performed at 6 weeks and 6 months 18

19. For children who are not breastfeeding, at age 6 weeks, • If a DNA PCR test is positive, the child is HIV-infected.Refer for treatment care and support. Once confirmed HIV infected stop daily NVP prophylaxis • If a DNA PCR is negative, the child is not HIV-infected. 19

20. For children who are breastfeeding, at age of 6 weeks • If a DNA PCR test is positive, the child is considered HIV-infected. Refer for treatment care and support. Once confirmed HIV infected stop daily NVP prophylaxis and initiate on ART immediately. • If a DNA PCR test is negative at 6 weeks repeat DNA PCR 6 months • If a DNA PCR test is positive at 6 months, the child is considered HIV-infected. Refer for treatment care and support. Once confirmed HIV infected stop daily NVP prophylaxis and initiate on ART immediately. 20

21. For children who are breastfeeding, at age of 6 weeks • If a DNA PCR test is negative at 6 months do serology test at 12 months • If the serology test is positive at 12 months , do a PCR test to confirm infection and if positive the child is considered HIV-infected. Refer for treatment care and support. Once confirmed HIV infected stop daily NVP prophylaxis and initiate on ART immediately • If the serology test is negative at 12 months ,counsel mother to consider cessation of breastfeeding. 21

22. For children who are breastfeeding, at age of 6 weeks • Final test should be done at 18 months, ( or 6 weeks after ceasation of breastfeeding). • If positive the child is considered HIV-infected. Refer for treatment care and support. Once confirmed HIV infected stop daily NVP prophylaxis and initiate on ART immediately. • If a DNA PCR test is positive 6 weeks after complete cessation of breastfeeding, the child is HIV-infected. • If Child is HIV Negative but is ill or fails to thrive refer for further evaluation and management of other illnesses 22

23. Window Period • After a person is infected with HIV, there is a period of time when s/he will not test positive for HIV because the antibodies are in undetectable quantities but they can infect other people. This is called the window period, and it can last from several weeks to three months. 23

24. The Window Period • The window period when using HIV DNA PCR is typically up to 6 weeks after last exposure • For HIV RAPID test, this period is typically 3 months after last exposure 24

25. HIV Testing in PMTCT • Testing should be done within antenatal care services using opt-out approach. • Results will be received on the same day and plan for care immediately. 25

26. HIV Testing • Screening test – Determine – high sensitivity • Confirmatory test – Unigold – High specificity • DNA PCR – definitive diagnosis for children 26

27. HIV Testing Algorithm • An HIV testing algorithm is a system used to conduct HIV tests designed to capture TRUE positive and TRUE negative results leading to a minimum of FALSE positive and FALSE negatives 27

28. First test/screening test • Abbott /Determine • High sensitivity • Negativetest result • Client is told s/he is not infected with HIV (see Module 6: Counselling) • Post-test counselling should include discussion of window period (recent exposure risk) and recommendation to retest in 3 months Non-reactive test result Reactive test result • Second test/confirmatory test • Unigold • High specificity • Positive test result • Client is told s/he is HIV-infected (see Module 6: Counselling) • Post-test counselling to include discussion of treatment and care options Reactive test result Non-reactive test result Refer specimen to a reference laboratory Third test/tie-breaker test for discordant test results (Bioline) HIV Testing Algorithm 28

29. Interpreting HIV Screening and Confirmation Test Results 29

30. Conducting the Rapid Test • Collect necessary equipment • Be sure to check the expiration date for each test • Label test strip or device with patients / sample ID code • Perform the test as per instructions • Ensure the test is valid • Read the test results accurately 30

31. ScreeningTestDetermine 31

32. Collect test items and other necessary lab supplies 32

33. Label the test strip with client identification number 33

34. Pull off the protective foil cover 34

35. Collection of specimen 35

36. Apply the specimen to the absorbent pad on the strip. 36

37. For whole blood only add 1 drop of chase buffer to the specimen pad. 37

38. Wait 15 minutes (no longer than 60 minutes) before reading the results 38

39. Read and record the results and other pertinent info on the worksheet 39

40. How to Read the HIV Rapid Test Result Accurately • Every HIV rapid test strip has a control line area and test result line area • The control line area is on top and the test result line area is at the bottom 40

41. HIV Positive Results 41

42. HIV NEGATIVE RESULTS 42

43. INVALID RESULTS 43

44. Test Results • Valid • Negative test • Positive test • Indeterminate • Invalid test 44

45. Uni-Gold 45

46. Procedure for performing Unigold • Check kit before use. • Use only items that have not expired or been damaged. • Bring kit and previously stored specimen to room temperature prior to use. • Always use universal safety precautions when handling specimens. 46

47. Collect test items and other necessary lab supplies 47

48. Remove device from package and label with client identification. 48

49. Collect blood specimen 1 49

50. Collect specimen 2 50