Hemolyzed Laboratory Specimens in the Emergency Department: An Underappreciated, but Frequent Problem

Hemolysis of blood samples from emergency department (ED) patients leads to delays in treatment and disposition. The aim of this study is to determine the frequency of hemolysis and variables predictive of hemolysis.

This observational cohort study was conducted among three institutions: academic tertiary care center and two suburban community EDs, with an annual census of over 270,000 ED visits. Data were obtained from the electronic health record. Adults requiring laboratory analysis with at least one peripheral intravenous catheter (PIVC) inserted within the ED were eligible. Primary outcome was hemolysis of lab samples and secondary outcomes included variables related to PIVC failure.

Between January 8, 2021 and May 9, 2022, 141,609 patient encounters met inclusion criteria. The average age was 55.5 and 57.5% of patients were female. Hemolysis occurred in 24,359 (17.2%) samples. In a multivariate analysis, when compared to 20-gauge catheters, smaller 22-gauge catheters had an increased odds of hemolysis (OR 1.78, 95% confidence interval (CI) 1.65-1.91; P < .001), while larger 18-gauge catheters had a lower odds of hemolysis (OR 0.94; 95% CI 0.90-0.98; P = .0046). Additionally, when compared to antecubital placement, hand/wrist placement demonstrated increased odds of hemolysis (OR 2.06; 95% CI 1.97-2.15; P < .001). Finally, hemolysis was associated with a higher rate of PIVC failure (OR 1.06; 95%CI 1.00-1.13; P = 0.043).

This large observational analysis demonstrates that lab hemolysis of is a frequent occurrence among ED patients. Given the added risk of hemolysis with certain placement variables, clinicians should consider catheter gauge/placement location to avoid hemolysis that may result in patient care delays and prolonged hospital stays.