PB0115 - Pre – analytical variables: A take on haemolysis and ways of dealing with it as reported by the United Kingdom National External Quality Assessment Scheme for Blood Coagulation (UK NEQAS BC).

Background: Haemolysis remains the leading source of pre – analytical errors encountered by laboratories performing coagulation tests on daily basis.

Aims: To investigate current haemolysed sample processing and rejection trends in coagulation laboratories registered in the UK NEQAS BC programme.

Methods: In November 2022 we distributed a questionnaire to 422 participants registered in external quality assessment programme (EQA) and asked them to provide answers about their approach to dealing with haemolysis flags reported by automated testing platforms, including strategies used to deal with different levels of haemolysis, reporting results. Responses were received from 281 (67%) centres.

Results: For sample rejection purposes, 71% of centres stated that their analyser would indicate the presence of haemolysis in the tested sample while 29% stated that their platforms would not. 34% reported they only use visual checks, 44% stated using both visual sample checks and analyser flags, with 22% just analyser flags for sample rejections. Of centres that were using visual checks only and in combination with analyser flags to reject haemolysed samples, 79% admitted not using any objective criteria for visual sample checks (colour charts) while 21% indicated using such criteria. For those using analyser flags, 74% indicated testing samples at one wavelength only, while 26% reported having a second wavelength setting on their platform for testing samples with haemolysis above a set haemolysis index (HI) threshold.
Most responses (91%) stated that the final decision about haemolysed sample rejection is made by a laboratory scientist and 9% indicated that samples with haemolysis would be automatically rejected.

Conclusion(s): Despite the increasing use of automated detection system for haemolysis, some centres use only subjective criteria to reject samples when performing visual checks. Standardisation of criteria used for haemolysis assessment at the preanalytical stage of sample processing is necessary to reduce clinical implications caused by haemolysed sample mismanagement in testing laboratories.