Effect of Sample Hemolysis on D-dimer Test Results in Patients with Suspected Pulmonary Embolism – A Retrospective Study

CONTEXT: Hemolysis within blood samples can impact the accuracy of D-dimer values, potentially affecting the diagnostic threshold for ruling out pulmonary embolism (PE) in patients. AIMS: This study aimed to assess the influence of sample hemolysis on D-dimer measurements and its consequential impact on patient management, particularly concerning the general and age-adapted diagnostic rule-out thresholds. SETTINGS AND DESIGNS: Retrospective evaluation of D-dimer values was conducted in patients presenting with suspected PE, determined by the Wells score. SUBJECTS AND METHODS: The effect of a maximal bias of 3.4% was assumed as worst-case scenario, a shift from a D-D above the general (≥0.5 mg/L) or the age-adapted rule (age × 10, if age >50 years) defined as clinically relevant due to its potential to miss a PE due to overuse of computed tomography pulmonary angiography in older patient. STATISTICAL ANALYSIS USED: Semi-autonomous were analyzed using the %2-test and continuous ones using the Mann–Whitney U -test. RESULTS: Out of 293 patients (53.9% were men, and the average age was 64 ± 17 years old), 63.1% of patients had verified PE. Hemolysis appeared in 19.1% of samples, mainly mild/moderate. The 3.4% bias correction reduced one D-dimer value to below the age-adapted cutoff and one below the general one without any involvement of hemolysis in either. CONCLUSIONS: There is minimal clinical effect of hemolysis on the D-dimension rule-out of PE and rare effects of threshold shifting. Interpretation of D-dimer results is very important to prevent errors in diagnosis.