When RBCs from an automated count are found to be abnormal, many laboratories will microscopically evaluate the blood morphology. This important step can help to establish which, if any, abnormalities are present as well as correlate possible disease states or conditions associated with the findings.
Most laboratories will employ guidelines for review of the peripheral blood smear for RBC morphology. Though each laboratory will create its own guidelines, the following are a few examples that could trigger a manual, microscopic peripheral blood smear review:
- Hemoglobin: < 8 or >18 g/dL (<10 or > 21g/dL in a newborn)
- Hematocrit: <20% or > 60% in adults (<40% or >65% in a newborn)
- MCHC: <29 g/dL
- MCV: <69 femtoliters (fL) or >110fL
- Flags generated by the hematology analyzer that indicate possible red cell abnormalities or spurious results
