Effects of haemolysis, icterus and lipaemia on coagulation tests as performed on Stago STA‐Compact‐Max analyser

Abstract

Summary Introduction Haemolysis, icterus and lipaemia (HIL) may affect haemostasis test results. This may be influenced by the level of interfering substance and the reagents and end‐point detection system used. Methods We assessed the influence of HIL on prothrombin time, activated partial thromboplastin time and fibrinogen assay using a viscosity‐based detection analyser. Results Spontaneous haemolysis that occurred during sample collection and processing had no effect on PT with either a rabbit tissue factor extract or recombinant human tissue factor reagents. In contrast, addition of mechanically haemolysed cells impacted on PT for the highest haemoglobin concentration. For APTTs determined with STA®‐Cephascreen® reagent, there was no significant difference between results in haemolysed and nonhaemolysed samples. For the other two reagents studied, APTTs were statistically significantly shorter in haemolysed samples compared with nonhaemolysed samples. This bias was clinically significant only for STA®‐PTT Automate. For all three APTT reagents, the impact of haemolysis was sufficient to impact patient management decisions, and in some samples, the effects of lipaemia and icterus were not clinically significant. Conclusion Overall, our results confirm that PT and fibrinogen were not clinically significantly affected by HIL. The APTTs of some haemolysed samples were falsely normal. Haemolysed samples for APTT determination should be rejected.

Performance of the preanalytical check module of the Stago STA R Max2 mechanical endpoint detection analyzer for assessing the impact of hemolysis, lipemia, and icterus on aPTT and PT

“…It was our aim to test the performance of this HIL detection and to establish a cut-off for result rejection due to HIL interference for routine PT and aPTT measurements. These findings are also in contrast with previous results published by Woolley et al,4 where no clinically significant difference for PT was withheld for patient samples or spiked samples. A possible explanation for this discrepancy may be that hemolysis was triggered using a different method and hence the effect on coagulation assays may be different.…”

Hemolysis interference in 10 coagulation assays on an instrument with viscosity‐based, chromogenic, and turbidimetric clot detection

“…The potential interference of hemolysis on PT and APTT assays has been the subject of several studies. 7,[13][14][15][16][17]27,28 However, different combination of reagents and instrumentations makes the comparison between these studies cumbersome. 1 Stago STA R instruments have a viscoelastic mechanical clot detection.…”

“…1 Stago STA R instruments have a viscoelastic mechanical clot detection. 7,14,17,18 Besides that, the content in the reagent kits varies among the manufacturers and many of the manufacturers offer more than one assay for the same analysis, for example, Stago offers four different assays for PT.…”

“…In some of the hemolysis studies in coagulation assays, a second sample has been requested when the initial sample from a patient was found to be hemolyzed. 14,15 Even though this is a smart study design and give more representative samples, that approach is time-consuming and it is difficult to cover the whole concentration range of interest that are needed to determine a cutoff concentration where the samples should be suppressed. That is probably is the reason why in vitro induced hemolysis is the most commonly used method to study the influence of hemolysis.…”

“…Another approach is to ask for a second replacement sample for a hemolyzed patient sample. 13,14 That study design will probably give the most correct answer, but it is laborious and the hemolysis level is hard to control for the laboratory.…”