A-325 Optimizing Management of Hemolyzed Specimens: Enhancing Clinical Value and Reducing Troponin and Potassium Recollections

Abstract

Hemolysis is a common and clinically significant preanalytical interference. It occurs when red blood cells break down and release intracellular contents into the matrix. Hemolysis causes both analytical interference and true concentration changes. Clinical laboratories routinely assess the degree of hemolysis to determine specimen suitability. Troponin T (TnT) and potassium are two analytes that are particularly susceptible to hemolysis-related bias. TnT is a key marker for detecting acute myocardial infarction (MI). TnT is measured serially at baseline and at two hours. The change is calculated between the two samples to rule in or out MI. Hemolysis can falsely lower TnT. According to Roche, the assay shows interference at an H index (HI) of 100. In our lab, about 3026 samples (5.5%) are rejected annually for high HI. These rejections require recollection, which can disrupt testing and delay patient care. Plasma potassium is routinely used to assess electrolyte imbalance, cardiac arrhythmias, and renal dysfunction. Because intracellular potassium concentrations are considerably higher than plasma concentrations, even mild hemolysis can falsely increase potassium levels. Due to the importance of accurate TnT and potassium testing for patient management, we studied hemolysis effects across a range of concentrations. We assessed the impact of hemolysis on TnT and potassium by simulating hemolytic conditions commonly observed in routine laboratory testing. Hemolysate was prepared from residual EDTA whole blood. Cells were washed three times with normal saline and then lysed with deionized water. Samples were collected to form eight pools with TnT concentrations ranging from 10 to 220 ng/L. Plasma pools were aliquoted and spiked with increasing levels of hemolysate (HI 20-349). Because non-hemolyzed specimens with naturally high potassium concentrations are difficult to obtain, a potassium chloride (KCl) stock solution was prepared in synthetic plasma. This solution was spiked into plasma pools to achieve target potassium concentrations from 2.1 to 7.5 mmol/L. Pools were tested neat and again after spiking with hemolysate (HI 0-600). To evaluate hemolysis interference, results at each hemolysis index level were compared with the corresponding baseline (non-hemolyzed) values. Increasing hemolysis caused a consistent decrease in TnT concentrations, with a more pronounced negative bias at higher hemolysis index levels. This effect was most clinically relevant near diagnostic cutoffs for myocardial infarction, where small changes can alter clinical interpretation. The data also showed that the degree of interference varies with baseline TnT concentration, supporting the use of tiered interpretive limits. Potassium concentrations increased steadily in proportion to hemolysis severity. Mild hemolysis produced small but measurable elevations, while moderate to severe hemolysis produced changes large enough to significantly affect clinical decision making. Optimizing laboratory practices for handling hemolyzed specimens improves testing efficiency and patient care. For TnT, HI tiered approach reduces unnecessary specimen rejections, lowers recollection rates and accelerates result reporting. For potassium, structured, evidence-based hemolysis comments help clinicians interpret results affected by hemolysis and reduce inappropriate treatment decisions. These strategies support practical and patient-centered approach to managing hemolyzed samples, enhancing the clinical value of laboratory testing.