Journal Article

Effectiveness of “Special Handling Instructions” to Reduce Hemolyzed Specimens in Hospitalized Patients

Kenyon, Stacy, Wittwer, Craig, Katzman, Brooke, Baumann, Nikola

2018

Overview

Abstract Hemolysis is a common preanalytical issue in the clinical laboratory, often causing a delay in test results and requiring patients to have blood re-collected to obtain acceptable specimens. Most specimen hemolysis occurs in vitro because of blood collection issues and/or handling/transport conditions. Special handling instructions (SHIs) were developed for hospitalized patients with two consecutive blood collections that are hemolyzed beyond the acceptable threshold for the physician-ordered tests. SHIs are managed by clinical chemistry fellows/residents and include specimen collection in a lithium heparin blood gas syringe followed by hand delivery to the laboratory. This process has been in place for several years, yet there have been no studies to quantitate how effectively SHIs reduce specimen hemolysis. The objective of this study was to determine if SHIs effectively reduce specimen hemolysis to allow reporting of laboratory test results. This study met criteria for a quality assurance/improvement initiative and did not require Mayo Clinic IRB review. Ninety-eight SHIs were reviewed between May and December 2017. Analytes (potassium [K], aspartate aminotransferase [AST], direct bilirubin [Dbil], lactate dehydrogenase [LDH], alkaline phosphatase [ALP], and total bilirubin [Tbil]) were measured in serum/plasma using Roche Cobas c701/c501/c502 analyzers and hemolysis was assessed using hemolysis index (H-index) (Roche Diagnostics, Indianapolis, IN). Analyte-specific H-index thresholds were used to prevent release of results and trigger specimen re-collection when H-index thresholds were exceeded. For each case, the time of collection, H-index, and analyte were obtained for the hemolyzed specimen that initiated SHI (pre-SHI) and the first sample collected after SHI implementation (post-SHI). The time between pre- and post-SHI collections (Δt), the percent difference in H-index (ΔH), and the percentage of results that were able to be reported after implementation of SHIs were calculated. The median Δt was 3.5 hours (interquartile range [IQR], 2.2–6.4). The median H-index pre-SHI and post-SHI was 215 (IQR: 150–400) and 18 (IQR: 6–55), respectively (P < .0001). The median ΔH between pre- and post-SHI was –93% (95% confidence interval [CI], –95 to –89%). Potassium was the analyte most likely to initiate SHI (n = 64, H-index threshold: 125), followed by AST (n = 20, concentration-dependent H-index: 50–500), Dbil (n = 8, concentration-dependent H-index: 50–70), LDH (n = 4, H-index: 50), ALP (n = 1, H-index: 200), and Tbil (n = 1, H-index: 400). Post-SHI, 89% (57/64) of K, 80% (16/20) of AST, 75% (6/8) of Dbil, 75% (3/4) of LDH, and 100% (1/1) of ALP and Tbil results were able to be reported because the H-index values were below the interference threshold. From this cohort of patients with repeatedly hemolyzed specimens, collecting blood using SHI significantly reduced specimen hemolysis and allowed the majority of results to be reported.

• Publisher: Oxford University Press
• Subject: Alkaline phosphatase / Aspartate aminotransferase / Bilirubin / Blood / Hemolysis / Heparin / Hirsch index / L-Lactate dehydrogenase / Laboratories / Lactic acid / Lithium / Potassium / Quality assurance