The research team/investigator/nurse/professional health care workers will teach the participants how to read the results for TST test. The investigator will compare the reading results done by the participants to the results read by the nurses.

This is a cross-sectional study of HIV-infected patients from 2 HIV clinics in Bangkok: HIV-NAT, Thai Red Cross AIDS Research Centre and Taksin Hospital. Research team/investigator/nurse/professional health care workers will assess whether the reading of TST test between the participants and the nurses are the same or not. The investigator and team believe that the readings of the TST tests between the participants and the nurses will be the same. If the investigator and team hypothesis is correct, then this will lessen the workload of the nurses and reduce the number of times the participants have to come to the clinic to see the nurses and the doctors. This is a pilot study to test this innovative method to teach the participants to read the TST results by themselves. If this technique is successful, then the investigator and team can expand the method to other hospitals in Thailand as well as in the region.

Inclusion Criteria:

1. Documented HIV-1 infection
2. Aged ≥18 years old
3. No sign and symptom of active TB

Exclusion Criteria:

1. Refuse to read TST by themselves

HIV-infected adults with documented HIV diagnosis who do not have any signs or symptoms of active TB.