METHODS AND TECHNIQUES

A breath test to assess compliance with disulfiram

ABSTRACT

Aims  To evaluate the ability of a hand-held breath analyser, the Zenalyser^® (Zenics Medical), to identify alcohol-dependent patients receiving disulfiram therapy and to assess the sensitivity and specificity of the instrument at different time intervals post-disulfiram dosing.

Design  Breath samples were taken from two groups of alcohol-dependent patients, one group on a daily disulfiram regimen and one group receiving no disulfiram. The breath samples were analysed for the combined concentration of carbon disulphide and acetone produced from the metabolism of disulfiram. From these data, two reference ranges were prepared and used for sensitivity and specificity assessments.

Setting  Breath samples for the reference ranges were obtained from patients at Shelton Hospital, Shrewsbury. Breath samples used to assess the sensitivity and specificity of the instrument were obtained from patients at the Edinburgh Alcohol Problems Clinic.

Participants  Twenty in-patients from Shelton Hospital receiving a daily 200 mg disulfiram regimen and 20 in-patients receiving no disulfiram. At the Edinburgh Clinic, 54 patients taking a thrice-weekly disulfiram regimen and 22 patients not on disulfiram.

Measurements  A total of 489 breath samples from Shelton Hospital and 391 breath samples from the Edinburgh Clinic were analysed for the combined concentrations of carbon disulphide and acetone.

Findings  The breath analyser produced results that distinguished between the disulfiram-treated and untreated groups (P < 0.001). At 1 day post-dose, the sensitivity was 100% and the specificity was 100%. At 2 and 3 days post-dose, the sensitivities and specificities were 84.6% and 100% and 88.2% and 100%, respectively.

Conclusion  The breath analyser can improve the assessment of the compliance status of patients receiving a daily dose regimen of disulfiram, but is less useful for this purpose if disulfiram is taken on a thrice-weekly regimen.