Practices for Identifying and Rejecting Hemolyzed Specimens in Europe

I read with interest the article of Howanitz and colleagues,¹  who carried out a large survey in the United States to assess the practices for identifying and rejecting hemolyzed specimens in clinical laboratories. Notably, the results of this survey clearly show that hemolysis practices vary widely.

In 2009, a similar survey was launched under the auspices of the European Scientific Advisory Board (ESAB, now Global Preanalytical Scientific Committee),²  collecting data from as many as 156 European laboratories. The survey, which was made available on the ESAB Web site (now Specimencare.com), was opened for 6 months and contained 2 specific questions about practices for identifying and rejecting hemolyzed specimens. More specifically, the laboratories were asked to indicate the overall prevalence of hemolysis in serum or plasma samples, the approach used to identify hemolyzed specimens, as well as their management.

Interestingly, in the ESAB survey the prevalence of hemolyzed samples exhibited a skewed distribution, with 45 of 156 laboratories (29%) reporting an overall hemolysis rate below 1%; and 66 of 156 (42%), between 1% and 2.9%, respectively (Figure). These figures are hence identical to those reported by Howanitz et al,¹  since a hemolysis rate below 2.9% was observed in exactly 71% of laboratories in both the ESAB and College of American Pathologists (CAP) surveys.¹  A hemolysis rate greater than 10% was reported by 2 of 156 European laboratories (1.3%), which is also in agreement with CAP data (1% of responders indicated a hemolysis rate > 15%).¹  Data collected for the second question of the ESAB survey (ie, the local approach for identifying hemolyzed samples) showed that most laboratories were using visual inspection (87 of 156; 56%), whereas the hemolysis index was used in 42% of laboratories (66 of 156). Interestingly, only 3 of 156 laboratories (1.9%) did not use any approach for identification of unsuitable samples. Compared to the CAP survey, automatic assessment (ie, instrument scale) was hence more widespread in Europe than the United States (42% versus 11%). Regarding the management of hemolyzed specimens, 24 of 156 European laboratories (15%) did not respond to this question, 83 of 132 respondents (63%) performed all requested tests without reporting those mostly affected by hemolysis, whereas 49 of 132 respondents (37%) rejected the specimen or refused to perform the tests biased by hemolysis. The rejection rate in Europe was hence less than half of that observed in the CAP survey (ie, 88%).

Some important conclusions can be made by comparing the data of the ESAB and CAP surveys. First, the rate of hemolyzed specimens is virtually identical in Europe and the United States, with nearly one third of responders indicating meaningful frequencies (ie, >3%). An objective approach for hemolysis identification (ie, the hemolysis index) appears more widespread in Europe than in the United States. Conversely, the rejection of hemolyzed specimens was commonplace in the United States, whereas only a minority of European laboratories used this more appropriate approach. Finally, European data support the conclusions of the CAP survey that standard assessment and consistent reporting should be regarded as foremost steps for reducing interlaboratory variability of hemolysis practices both in Europe and the United States.³