Is the hemolysis index always suitable for monitoring phlebotomy performance?

The new generation of clinical chemistry and coagulation analyzers is equipped with technical features allowing a systematic check of sample quality, including an assessment of the so-called HIL (“hemolysis”, “icterus”, “lipemia”) indices. These measures enable an accurate and reproducible assessment of sample hemolysis in serum or plasma, hence the hemolysis index (H-index) is now also increasingly used for monitoring and benchmarking phlebotomy performance. Reliable evidence attests that intravascular hemolysis is not such a rare phenomenon, and its prevalence may be especially higher in geographical areas where congenital hemolytic diseases are endemic, as well as in healthcare settings where patients with acquired hemolytic disorders are more frequently visited or hospitalized. It is hence conceivable that monitoring phlebotomy performance based on the rate of hemolyzed specimens received by the laboratory may not be so straightforward, provided that specimens drawn from patients with intravascular hemolysis can be identified and excluded from the analysis. The aim of this article is to provide an overview of potential drawbacks in using the H-index alone for monitoring phlebotomy performance, and to offer potential solutions to improve its efficiency for this scope. We therefore suggest that the H-index may only be used for purposes of benchmarking phlebotomy performance when the overall number of diagnoses of hemolytic diseases or the haptoglobin values measured by the laboratories are comparable across different healthcare settings or geographic areas.