HIV-1 antiretroviral resistance testing laboratories.

Objective: To identify and to describe the genotyping and the phenotyping testing practices of U.S. laboratories performing patient HIV-1 antiretroviral resistance testing.

Results of a physician survey on ordering viral load testing. Opportunity for laboratory consultation.

Objective: To profile physicians' practices, utilization, and understanding of human immunodeficiency virus type 1 RNA (viral load) testing and the laboratory's role in this testing.

Design: Cross sectional study using a 34-item self-report survey mailed to physicians identified as requesting viral load testing, with follow-up mailings to nonresponders.

Participants: A sampling of US physicians specializing in infectious diseases, internal medicine, and family practice associated with high, medium, and low human immunodeficiency virus/acquired immunodeficiency syndrome incidence areas.