Interpretation and Management of MCHC 28.7 and RDW 15.4
The combination of a low MCHC (28.7) and elevated RDW (15.4) strongly indicates iron deficiency anemia and requires prompt iron supplementation therapy along with diagnostic workup to identify the underlying cause.
Diagnostic Significance
The laboratory values provide important diagnostic information:
- MCHC (Mean Corpuscular Hemoglobin Concentration) of 28.7: This is below the normal range, indicating hypochromia (reduced hemoglobin concentration in red blood cells)
- RDW (Red Blood Cell Distribution Width) of 15.4: This is elevated above the normal cutoff of 14.0%, indicating increased variation in red blood cell size (anisocytosis)
According to CDC guidelines, this specific pattern is highly suggestive of iron deficiency anemia:
- A low MCHC indicates reduced hemoglobin concentration in red cells
- An RDW >14.0% with low MCHC strongly points to iron deficiency anemia rather than thalassemia minor 1
This combination is particularly important for differential diagnosis:
- Iron deficiency anemia: Low MCHC + High RDW (>14.0%)
- Thalassemia minor: Low MCHC + Normal RDW (≤14.0%) 1
Recommended Management Approach
1. Complete Diagnostic Workup
- Obtain complete blood count with hemoglobin measurement
- Check iron studies:
- Serum ferritin (target >100 ng/mL)
- Transferrin saturation (target >20%) 2
- Consider hemoglobin electrophoresis if thalassemia remains a concern despite the RDW pattern
2. Iron Supplementation
- Initial treatment: Oral iron supplementation with ferrous sulfate, fumarate, or gluconate, one tablet daily 2
- Duration: Continue for approximately 3 months after normalization of hemoglobin levels
- Monitoring: Check hemoglobin response after 4 weeks of iron therapy 2
3. Identify and Address Underlying Cause
Common causes to investigate include:
- Gastrointestinal blood loss (especially in adults)
- Menstrual blood loss in women of reproductive age
- Malabsorption disorders
- Poor dietary intake
- Increased iron requirements (pregnancy, rapid growth in children)
4. Monitoring Response
- Monitor hemoglobin, MCHC, and RDW every 4 weeks initially
- Target normalization of MCHC and reduction in RDW toward normal range
- If no improvement after 4-8 weeks of oral iron therapy, consider:
- Evaluating compliance
- Switching to intravenous iron if absorption issues are suspected
- Reassessing diagnosis if values don't improve despite adequate therapy
Special Considerations
False elevation of MCHC: In rare cases, MCHC can be falsely elevated due to cold agglutination or lipid interference. However, this case shows a low MCHC, not an elevated one 3
Predictive value: Studies show that MCV, MCH, and RDW have good predictive value for iron deficiency anemia, with MCV having the highest accuracy (ROC curve=0.768), followed by MCH (ROC curve=0.72) and RDW (ROC curve=0.711) 4
Renal function: In patients with reduced renal function, the predictive value of RDW for iron deficiency may be lower 5
Conclusion
The combination of low MCHC (28.7) and elevated RDW (15.4) is highly suggestive of iron deficiency anemia. Management should focus on iron supplementation and identifying the underlying cause of iron deficiency to prevent recurrence.