Premium
Leukocytosis: A New Look at an Old Marker for Acute Myocardial Infarction
Author(s) -
Green Steven M.,
Vowels John,
Waterman Bruce,
Rothrock Steven G.,
Kuniyoshi Gary
Publication year - 1996
Publication title -
academic emergency medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.221
H-Index - 124
eISSN - 1553-2712
pISSN - 1069-6563
DOI - 10.1111/j.1553-2712.1996.tb03350.x
Subject(s) - medicine , leukocytosis , myocardial infarction , white blood cell , creatine kinase , absolute neutrophil count , logistic regression , predictive value of tests , receiver operating characteristic , gastroenterology , odds ratio , cardiology , chemotherapy , neutropenia
Objective: To determine the test performance of leukocytosis for identifying acute myocardial infarction (AMI) in patients with nondiagnostic ECGs, admitted to rule out AMI. Methods: A retrospective, comparative test performance study was conducted using patients admitted to a university teaching hospital to rule out AMI. Clinical and laboratory information was reviewed and hospital laboratory ranges were used to define threshold elevations: total creatine kinase (CK), 275 U/L; CK‐MB, 7.5 μg/L; white blood cell (WBC) count, 11.5 × 10 9 /L; and absolute neutrophil count (ANC), 8.0 × 10 9 . Sensitivity, specificity, and predictive values of the total CK, CK‐MB, WBC count, and ANC were calculated, and receiver operating characteristic (ROC) curves constructed. Test performances of marker combinations also were determined. Results: The initial WBC count was significantly higher for the subjects who had AMI (11.1 vs 8.8 × 10 9 /L, p < 0.001). For the 688 subjects who had nondiagnostic ECGs, sensitivities for the initial total CK, CK‐MB, WBC, and ANC were 39%, 73%, 35%, and 36%, respectively, while the corresponding specificities were 94%, 93%, 85%, and 86%. Logistic regression analysis confirmed leukocytosis as an independent predictor of AMI (adjusted odds ratio 4.08, 95% CI 1.73–9.63). While CK‐MB alone was 73% sensitive for AMI, the decision rule of either an elevated CK‐MB or an elevated WBC count increased this sensitivity to 88% (corresponding specificity 79%). Similarly, while CK‐MB alone was 93% specific for AMI, the combination of an elevated CK‐MB and an elevated WBC count increased this specificity to 99% (corresponding sensitivity 20%). Conclusions: Leukocytosis is significantly associated with AMI, and is a weak but independent laboratory predictor of this condition. In this preliminary study of admitted patients suspected of AMI, the combination of the WBC and the CK‐MB may have, additional diagnostic value over an isolated CK‐MB result. Neither parameter in isolation was satisfactorily sensitive for AMI. Prognostic assessment of the role of the WBC count in clinical decision making should address its complementary role to that of other clinical and ancillary test parameters.