New medical technologies and clinical practice: a survey of lymphocyte subset monitoring.

BACKGROUND: Since its inception in the early 1980s, lymphocyte subset (LS) monitoring of transplant patients has been a controversial technique. The clinical literature is replete with contradictory claims concerning its usefulness. No systematic information is however available on clinicians' attitudes towards the new technology. METHOD: We carried out a mail survey of the members of The Transplantation Society concerning the availability, use, value, and critical assessment of LS monitoring. RESULTS: Results show that LS monitoring technology is available in most clinical settings surveyed and is regularly used by about half of the respondents associated with a clinical transplant program. About half of the users obtain diagnostically relevant measurements (T4/T8 ratios), as opposed to measurements related to OKT3 anti-rejection therapy. While claiming that LS measurement is a useful tool, respondents attribute a low average score to the diagnostic value of the technique; about 2/3 believe that its absence would not affect their clinical judgment. Finally, 25% of the respondents send blood for LS measurements although they do not believe the technique is useful. CONCLUSIONS: The results suggest that research instruments which generate clinical interest may develop clinical-diagnostic routines despite a lack of consensus concerning their usefulness. More importantly, these routines avoid a critical assessment of key notions such as "immune monitoring" which tend to blur the distinction between research and therapy.