A Methodical Approach to Interpreting the Red Blood Cell Parameters of the Complete Blood Count

Abstract

1. Kathy Doig, PhD, MLS(ASCP)CM SH(ASCP)CM[⇑][1] 1. Professor Emeritus, Biomedical Laboratory Diagnostics Program, Michigan State University, E. Lansing, MI 2. Bei Zhang, MD, PhD, MLS(ASCP)CM 1. Teaching Specialist, Biomedical Laboratory Diagnostics Program, Michigan State University, E. Lansing, MI 1. Address for Correspondence: Kathy Doig, PhD, MLS(ASCP)CM SH(ASCP)CM, 354 Farm Lane, Rm. N322, E. Lansing, MI 48824, 517-353-1985, doig{at}msu.edu 1. List the red blood cell parameters of the complete blood count (CBC). 2. Describe the principle of analysis for each of the red blood parameters of the CBC. 3. Explain the disadvantages of relative reticulocyte counts. 4. Given relative reticulocyte counts and red blood cell counts, calculate absolute reticulocyte counts. 5. Given a relative reticulocyte count and patient hematocrit and morphology, calculate the corrected reticulocyte count and reticulocyte production index, when needed. 6. Given the red blood cell parameters of a CBC, compare each to the reference interval and apply proper terminology to the interpretation of results outside the reference interval. 7. Given red blood cell parameters of a CBC, apply a methodical approach to assess the validity and reportability of results. 8. Apply a methodical approach to red blood cell parameters of the CBC to assess diagnostic and clinical significance. A methodical approach to interpreting the panel of complete blood count (CBC) results helps to ensure that spurious results are detected and corrected before results are reported and helps to ensure that no results are overlooked in a diagnostic analysis of the results. The steps to interpreting the red blood cell (rbc) parameters are: 1. Interpret the hemoglobin value relative to the appropriate reference interval. 2. Interpret the mean cell volume relative to the reference interval. 3. Interpret the mean cell hemoglobin concentration relative to the reference interval. 4. Interpret the red blood cell distribution width relative to the reference interval. 5. Examine the red blood cell morphology, if available, and correlate morphology with instrument parameters for consistency and quality purposes. Also, review for additional diagnostic findings. 6. As a final check on the numerical parameters, examine the rbc count, hematocrit, mean cell hemoglobin, and calculate the Rule of Three to ensure that the above interpretations are correct. 7. Use related test results when available, particularly reticulocyte parameters, to verify CBC findings and add diagnostic information. 8. Interpret the rbc parameters for diagnostic significance and correlate with results of white blood cell and platelet parameters. Explanations for conducting the evaluations are provided and the above steps are applied to examples to demonstrate this approach to interpreting the rbc parameters of the CBC. ABBREVIATIONS: CBC - complete blood count, CRC-corrected reticulocyte count, dL-deciliter, fL-femtoliter, rbc-red blood cell, RBC-red blood cell count, HB-hemoglobin, HCT-hematocrit, g-gram, IRF-immature reticulocyte fraction, MCV-mean cell volume, MCH-mean cell hemoglobin, MCHC - mean cell hemoglobin concentration, MLS-medical laboratory scientist, pg-picogram, plt-platelet, PLT-platelet count, RDW-red blood cell distribution width, RNA-ribonucleic acid, RPI-reticulocyte production index, wbc-white blood cell, WBC-white blood cell count, μL-microliter [1]: #corresp-1