CD4+ T-cell testing practices as implications for training

As new diseases and new testing methods emerge, clinical laboratories are faced with updating the skills of their personnel. Complex techniques, such as flow cytometry, require both education and experience to achieve a high level of proficiency. One of the ways to determine areas in which training is needed is to assess laboratory practices and compare them with practices recommended in guidelines or by panels of experts. In this paper we describe practices reported in a written survey of 206 laboratories that perform CD4+ T-cell counts (CD4). We provided a list of alternate practices for each of the key steps in the testing process and asked participants to select the practices they use in their laboratories. Published guidelines and interviews with knowledgeable "key informants" and focus groups of people who perform CD4 testing were used to formulate the questions. We interpreted variations from recommended practices as indicators of training needs. Other factors that can affect performance, such as workload, supervision, and resources, were satisfactory to the respondents. A response rate of 73% (247 of 337 laboratories) revealed that laboratories followed most of the recommended practices. Notable exceptions included some areas of quality control and quality assurance and safety. This paper also describes flow cytometry testing as it was practiced in 1993 shortly after release of some of the testing guidelines and provides a baseline of practices for that time frame.