Automated differentials in the hematology laboratory.

The white blood cell differential continues to be one of the most widely performed clinical laboratory procedures. However, its clinical usefulness is affected by sampling error and, to some extent, by classification criteria. It is also labor intensive and expensive to perform. Automated leukocyte differential instrumentation addresses many of the sources of error that occur with the manual differential. Current state-of-the-art instrumentation will give results that equal or exceed the routine manual differential. Because these instruments also examine red blood cell and platelet parameters, as well as providing white blood cell information, they can better screen for significant abnormalities as well as greatly reduce the expensive and time-consuming manual differential procedures.