Near patient cholesterol testing in patients with peripheral arterial disease

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).

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.

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 < or = 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.

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.