Near patient cholesterol testing in patients with peripheral arterial disease

Abstract

Aims: To assess the bias, precision and utility of the Bioscanner 2000 for near patient testing of total cholesterol (NPTC) in patients with peripheral arterial disease (PAD). Methods: One hundred consecutive patients attending a hospital-based clinic-with symptomatic PAD underwent non-fasting NPTC using finger prick blood sample and a laboratory total cholesterol (TC) using blood drawn from an antecubital fossa vein. Results: The Bioscanner 2000 showed good precision with a coefficient of variation of 1.8-3.8%. NPTC was significantly lower than laboratory TC (mean (S.D.) 4.67 (1.1) vs. 5.12 (1.2) mmol/l), p ≤ 0.01, paired Student's t-test. Comparing the two methods using Deming regression revealed a 15% negative bias for the Bioscanner 2000 compared to laboratory testing, which was demonstrated to be a systematic bias using a Bland-Altman plot. Almost half (46%) of the readings differed by > 0.5 mmol/l, 16% by > 1.0 mmol/l and 3% by > 2 mmol/l. This means that if the cut-off for statin treatment were taken as a TC of 5.0 or 3.5 mmol/l then, based on NPTC, alone 18 and 6% of patients, respectively, would not have received a statin. Conclusions: In the present study, NPTC significantly under-estimated TC when compared to laboratory testing. However, in the majority of cases, this would not have affected the decision to prescribe a statin and NPTC testing allows the immediate institution or titration of statin treatment.