Refrigerated storage improves the stability of the complete blood cell count and automated differential

Am J Clin Pathol. 1999 Nov;112(5):687-95. doi: 10.1093/ajcp/112.5.687.


A CBC count was performed on 113 random patient and 21 control specimens before and after 24-hour room temperature (RT) storage; 98 random patient and 20 control specimens also were analyzed before and after 24 hour 4 degrees C storage. The Cell-Dyn 3500 (Abbott Laboratories, Abbott Park, IL) was used for analysis. RT storage showed a decline in WBC count using the optical but not the impedance method, resulting in a large number of WBC flags. An increase in mean corpuscular volume also was seen for patient specimens. The automated WBC differential showed a decrease in the percentage of neutrophils and an increase in the percentage of lymphocytes, owing primarily to neutrophil degeneration. These changes also were seen in the manual differential to a similar degree. Storage of specimens at 4 degrees C largely prevented all of these changes. The implementation of refrigerated specimen storage is a simple, inexpensive method to improve the accuracy of CBC results for aged specimens on automated hematology analyzers.

Publication types

  • Comparative Study

MeSH terms

  • Autoanalysis / instrumentation
  • Blood Preservation / methods*
  • Cryopreservation / methods*
  • Evaluation Studies as Topic
  • Hematology / instrumentation
  • Humans
  • Leukocyte Count*
  • Random Allocation
  • Refrigeration
  • Reproducibility of Results
  • Temperature