Spinner films for reticulocyte counts

The widely practiced method for performing a reticulocyte count includes counting 1000 normal erythrocytes while searching for a relatively small population of reticulocytes. A method is presented using a spinner reticulocyte preparation which avoids the need to count the normal erythrocytes, thereby eliminating most of the tedium from the test. The accuracy and reproducibility of this new method, as compared to the currently practiced method, is presented, along with the results of an on-line comparison.