Automated and cost-efficient early detection of hemolysis in patients with extracorporeal life support: Use of the hemolysis-index of routine clinical chemistry platforms

Purpose: Patients with extracorporeal life support (ECLS) are at risk for hemolysis-related complications. Therefore, monitoring of free hemoglobin (fHb) levels is indicated. Conventional methods for fHb are laborious and not always available. Here we evaluated the suitability of the hemolysis-index (H-index), an internal quality control parameter of clinical chemistry platforms, as a clinical parameter for ECLS patients.

Materials and methods: The performance of the H-index assay was evaluated using standard procedures. Furthermore, H-index data from ECLS patients (n = 56) was analyzed retrospectively.

Results: The H-index significantly correlated with fHb and showed good analytical performance. During ECLS 19.6% of the patients had an H-index above 20 in at least 2 consecutive blood draws, indicating significant hemolysis. In the patients with clot formation in the pumphead the H-index peaked above 100. Visible clots at other locations did not always coincide with hemolysis. H-index peaks were more prevalent in patients that died during ECLS support.

Conclusions: We conclude that the H-index is a suitable and cost-efficient alternative for the conventional fHb analysis with good analytic performance. The H-index aids in the early detection of hemolysis in patients with ECLS. A repeated H-index>20 was a predictor of mortality.