Mild Anemia with Reactive Thrombocytosis Requiring Iron Studies and Evaluation
This patient has mild anemia (hemoglobin 108 g/L) with an elevated MCHC (297 g/L, which is abnormally low if this represents 29.7 g/dL) and reactive thrombocytosis (platelets 437 ×10⁹/L), most likely indicating iron deficiency anemia that requires immediate iron studies and investigation for underlying blood loss.
Initial Laboratory Evaluation
The first priority is completing a comprehensive anemia workup 1, 2, 3:
- Serum ferritin (most powerful test for iron deficiency; <12 μg/dL is diagnostic) 1
- Transferrin saturation (TSAT) (values <20-30% suggest iron deficiency)
- Complete blood count with indices including mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and red cell distribution width (RDW)
- Reticulocyte count to assess bone marrow response 3
- Vitamin B12 and folate levels to exclude combined deficiency 2
Critical Point About Your MCHC Value
The MCHC of 297 g/L appears to be a reporting error or unit confusion. Normal MCHC is 320-360 g/L (or 32-36 g/dL). If this actually represents 29.7 g/dL, this is hypochromic and strongly suggests iron deficiency 1. Recent evidence shows MCHC interferences can occur with certain analyzers, so verify this result 4.
Interpreting the Platelet Elevation
The elevated platelet count (437 ×10⁹/L) in the context of anemia is highly suggestive of iron deficiency. Research demonstrates a clear inverse relationship between iron stores and platelet counts 5, 6:
- Serum iron and transferrin saturation correlate negatively with platelet counts (r=-0.404 for serum iron) 6
- The more severe the iron deficiency, the higher the platelet count 6
- Platelet counts typically normalize after iron repletion 6
The platelet elevation here is reactive thrombocytosis, not a primary platelet disorder, and requires no specific treatment beyond addressing the underlying anemia 7.
Investigation for Blood Loss
Since this patient is not menstruating (based on context) or has other risk factors, gastrointestinal blood loss must be excluded 1:
- Upper endoscopy with small bowel biopsy (to exclude celiac disease, gastric cancer, peptic ulcer)
- Colonoscopy or barium enema (to exclude colorectal cancer, polyps, angiodysplasia)
- Consider NSAID use history, which is a common cause of occult GI bleeding 1
This investigation is mandatory in adults with iron deficiency anemia to exclude malignancy 1.
Iron Replacement Strategy
Based on iron study results 2, 8, 2:
If Ferritin <30 μg/L and/or TSAT <20%:
- Oral iron therapy: 100-200 mg elemental iron daily for 1-3 months in non-dialysis patients 2
- Intravenous iron: Consider if oral iron not tolerated, malabsorption suspected, or rapid correction needed 8, 2
If Ferritin 30-100 μg/L with TSAT <20%:
- Still indicates functional iron deficiency requiring supplementation 8
- Rule out concurrent inflammation (ferritin is an acute phase reactant) 1
If Ferritin >100 μg/L:
- Iron deficiency is unlikely; investigate other causes of anemia 1
Monitoring Response
After initiating iron therapy 1, 6:
- Hemoglobin should increase by approximately 1-2 g/dL within 3-4 weeks
- Platelet count should normalize as iron stores replete 6
- Reticulocyte count should rise within 7-10 days (indicating bone marrow response)
- Repeat complete blood count and iron studies at 3 months
Common Pitfalls to Avoid
Do not assume the platelet elevation requires hematologic workup unless it persists after anemia correction or exceeds 600 ×10⁹/L 7
Do not skip GI investigation even with mild anemia—asymptomatic malignancies can present this way 1
Verify the MCHC value as 297 g/L is physiologically implausible and likely represents a measurement artifact or unit error 4
Consider combined B12/folate deficiency if MCV is normal despite iron deficiency (the macrocytosis from B12 deficiency can mask the microcytosis from iron deficiency) 1, 9
Check for chronic kidney disease (serum creatinine and eGFR) as this can cause anemia with normal iron stores 2