A practical method for reducing the interference due to lipaemia in coagulation tests

INTRODUCTION: Plasma samples with gross lipaemia present a challenge for coagulation laboratories using optical analysers. High‐speed centrifugation may be used to remove excess lipids but it has not established whether this affects haemostasis tests. The aims were to determine whether the removal of lipid by centrifugation affects PT, APTT, fibrinogen, D‐dimer and von Willebrand factor activity measurements. METHODS: Twenty‐six lipaemic samples (median [range]): triglyceride 4.6 mmol/L [0.5‐17.0]; cholesterol: 4.06 mmol/L [2.20‐9.41] and 20 plasmas spiked with Intralipid 20 or lipid isolated from patient plasmas (median triglyceride of 11.95 mmol/L [5.0‐17.0] and cholesterol 4.33 [3.22‐7.06]), were tested before and after the removal of the lipid layer by centrifugation (10000 g for 10 minutes). Tests were performed using the CS‐5100 (Sysmex) coagulation analyser. RESULTS: Thirteen, 9, 3 and 1 of the lipaemic or spiked samples failed to give PT, APTT, fibrinogen and D‐dimer results, respectively. Centrifugation significantly reduced triglyceride (median 2.7, [0‐6.1 mmol/L]) and cholesterol (median 0.52 [0‐3.5]), allowing clot detection in all tests. There were no statistically significant differences in fibrinogen, D‐dimer or VWF levels in samples before and after lipid removal. A small but clinically insignificant change in PT and APTT was observed after lipid removal. CONCLUSION: High‐speed centrifugation reduces lipaemia sufficiently to allow testing on an optical coagulation analyser without introducing clinically significant differences PT, APTT, fibrinogen, D‐dimer or VWF activity values.