Capacity of US labs to provide TLI in support of early HIV-1 intervention.

We surveyed laboratories to assess their capacity to perform T-lymphocyte immunophenotyping. Of the 1026 respondents, 279 located in 41 states and the District of Columbia performed this type of testing. Most laboratories were located in hospitals, reported a low weekly test volume, and indicated that it took 6-24 weeks for flow cytometer operators to become proficient. Many laboratories appear to have the capacity to perform additional CD4+ cell testing, but training additional operators may be necessary. The paucity of laboratories performing T-lymphocyte immunophenotyping in the public sector may affect referral patterns from that setting.