1. What is the significance of blood indices in the classification of anemias?
- Quantitative erythrocyte measurements and peripheral blood smear tests are needed as essential
information when evaluating erythrocyte disorders. Essential erythrocyte measurements include
erythrocyte count, packed cell volume, and hemoglobin concentrations. For the evaluation of
erythrocytes, several mathematically derived parameters which constitutes the blood indices such as
MCV, the MCH and the MCHC are important. These are calculated in order to determine the sample 's
average volume and hemoglobin content and concentrations of red blood cells. In addition to acting as a
quality control check, the indices can be used for the initial anemia classification. Anemia is a condition
that comes in many forms; it may be directly due to a lack of RBC development or an abnormality in the
morphology of RBC-and many more-in which the output of RBC indices can help distinguish, diagnose
and narrow down to what abnormality is present.
2. How are different blood indices derived using automated hematology analyzers?
- Each automated analyzer has a specific way of deriving data, but the most important thing is to be able
to reliably collect the results (RBC count and Hgb). Via cumulative RBC pulse height detection, HCT can
be derived. By dividing the total hemoglobin by the RBC count and multiplying the quotient by 10 [(HGB
/ RBC) X 10], HCT (Hematocrit) and MCV (Mean Corpuscular Volume) are determined. By dividing total
hemoglobin with hematocrit and multiplying the quotient by 100 [(HGB / HCT) X 100], the MCHC (Mean
Corpuscular Hemoglobin Concentration) is then calculated. By dividing total hemoglobin by the red blood
cell count and multiplying the quotient by 10 [(HGB / RBC) X 10], MCH (Mean Corpuscular Height) is
derived.
3. What is red cell distribution width? What is its clinical significance?
- Red blood cells promote the exchange of essential gases and the transfer of nutrients. The size of RBCs
determines if they can serve that purpose effectively which leads to the red cell distribution width that
measures the volume and size of red blood cells. The red blood cell distribution width is a calculation of
the erythrocyte volume variability index and is regularly reported as part of a full count of blood cells.
RDW serves the same function as RBC indices, helping to distinguish whether or not the RBCS is affected
by anomalies. Elevated RDW shows increased variation in the size of red blood cells, suggesting an
altered life span of erythrocytes. Vitamin B2 deficiency resulting from macrocytic anemia may be
suggested by elevated RDW. In iron deficiency anemia, where anisocytosis is observed, also has an
elevated RDW. Both the RDW and the traditional index of erythrocytes, the MCV, provide quantitative
erythrocyte size descriptors. While RDW provides an early indicator of nutritional deficiency compared to
MCV, it is still important to note that the relationship between RDW and MCV can characterize various
erythrocytic disorders.
REFERENCES:
Anthony, K. (2019, September 20). Red Cell Distribution Width (RDW) Test. Healthline.
https://www.healthline.com/health/rdw-blood-test#results
Keohane, E. M., Smith, L. J., & Walenga, J. M. (2016). Rodak's hematology: Clinical principles
and applications. St. Louis, Missouri.: Elsevier/Saunders.
McPherson, R. A., & Pincus, M. R. (2017). Henry's clinical diagnosis and management by laboratory
methods. St. Louis, MO: Elsevier.