Algorithm for Differential Diagnosis of in Vitro and in Vivo Hemolysis in Anticoagulated Blood Specimens

Lee, Jong Han; Kim, Yoonjung; Yoo, Gilsung; Kim, Juwon; Yoon, Kap Jun; Uh, Young

Abstract

BACKGROUND
Hemolytic specimens contain components that interfere with clinical laboratory results. We evaluated previously published hemolysis indices (HI) and developed an algorithm for differentiating between mechanical hemolysis and immune-mediated hemolysis based on complete blood count (CBC).
METHODS
Sixty-three residual EDTA (ethylenediamine tetraacetic acid)-anticoagulated blood specimens were obtained during regular health check-ups, and each specimen was divided into 3 aliquots (A control, B, and C group). Aliquots B and C were mechanically hemolysed by 2 and 5 aspirations, respectively, using a 25-gauge needle before testing; aliquot A was analysed immediately without hemolysis. Additionally, we collected 36 specimens from patients suspected of having immune-mediated hemolysis after thorough reviewing their various laboratory results including direct antiglobulin test. We compared CBC parameters between the groups (A, B, C, D [B+C], and E [immune-mediated hemolysis group]).
RESULTS
Our HI scoring system using the sum of red blood cell ghosts, measured hemoglobin-calculated hemoglobin, mean corpuscular hemoglobin concentration-corpuscular hemoglobin concentration mean, and mean platelet volume rather than mean corpuscular hemoglobin, effectively identified mechanical hemolysis; the results were similar to those of previous studies. Furthermore, the HI score using the sum of mean corpuscular volume, red cell distribution width, hemoglobin distribution width, polymorphonuclear %, and neutrophil % differentiated mechanical hemolysis from immune-mediated hemolysis (cut-off, 9; sensitivity, 91.7%; specificity, 92.9%; area under the receiver operating characteristic curve, 0.965 [95% confidence interval, 0.924-0.988]).
CONCLUSIONS
The newly developed algorithm may provide effective screening for detecting hemolysis and differential diagnosis of mechanical hemolysis and immune-mediated hemolysis based on CBC results.