Understanding Your MCHC of 31.90 g/dL
Your MCHC of 31.90 g/dL is at the lower end of normal or slightly low, indicating mild hypochromia (reduced hemoglobin concentration in red blood cells), which most commonly suggests early iron deficiency that requires confirmation with iron studies before any treatment decisions. 1
What MCHC Measures and Why It Matters
Mean Corpuscular Hemoglobin Concentration (MCHC) measures how much hemoglobin is packed into your red blood cells. The normal range is typically 32-36 g/dL, so your value of 31.90 sits just at or slightly below the lower limit. 2
- Low MCHC indicates hypochromia, meaning your red blood cells contain less hemoglobin than normal, which most commonly points toward iron deficiency anemia 1
- However, MCHC alone cannot diagnose iron deficiency—you need confirmatory iron studies 2, 1
Immediate Next Steps: Required Testing
You must obtain iron studies to confirm or exclude iron deficiency before drawing any conclusions. The British Society of Gastroenterology strongly recommends the following tests: 2
- Serum ferritin (the single most specific test for iron deficiency) 2, 1
- Transferrin saturation (TSAT) 2, 1
- Complete blood count with MCV to assess if your red cells are also small (microcytic) 1
- Reticulocyte count to evaluate bone marrow response 1, 3
- C-reactive protein (CRP) to assess for inflammation that could affect ferritin interpretation 1
Interpreting Your Results Based on Iron Studies
If Iron Deficiency is Confirmed:
Ferritin interpretation depends on inflammation status: 1
- Ferritin <30 μg/L without inflammation = confirmed iron deficiency 1, 3
- Ferritin <100 μg/L with inflammation = possible iron deficiency 1
- TSAT <16-20% = supports iron deficiency 1
If iron deficiency is confirmed, you need: 1
- Investigation for the underlying cause (gastrointestinal bleeding is common in adults with no obvious source) 1, 3
- Oral iron supplementation as first-line: ferrous sulfate 325 mg (65 mg elemental iron) 1-3 times daily between meals 1
- Expected hemoglobin increase of 1-2 g/dL every 2-4 weeks 1
- Continue iron for 3-6 months after hemoglobin normalizes to replenish stores 1
If Iron Studies Are Normal:
Consider alternative diagnoses: 1, 3
- Thalassemia trait (especially if you have Mediterranean, Asian, or African ancestry)—obtain hemoglobin electrophoresis 2, 1
- Anemia of chronic disease (assess for underlying inflammatory conditions) 1, 3
- Sideroblastic anemia (rare) 2
Critical Pitfalls to Avoid
Do not assume iron deficiency without testing. While low MCHC suggests iron deficiency, other conditions can cause this finding, and treatment without confirmation can mask serious underlying conditions. 2
Do not dismiss normal ferritin if you have inflammation. Ferritin is an acute phase protein that rises with inflammation, so "normal" ferritin (30-100 μg/L) may still represent iron deficiency if you have any inflammatory condition. 2, 1
Do not ignore the need to find the source. In adults with confirmed iron deficiency and no obvious cause (like heavy menstrual bleeding), gastrointestinal evaluation is often necessary to exclude malignancy or other serious pathology. 1, 3
Why MCH Matters More Than MCHC
Mean Corpuscular Hemoglobin (MCH) is actually a more reliable marker of iron deficiency than MCHC because it's less dependent on laboratory equipment and storage conditions, and it decreases in both absolute and functional iron deficiency. 2, 1 If your MCH is also low, this strengthens the suspicion for iron deficiency even more.