Will a complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) with stool examination for ova and parasites provide a fair idea of chronic inflammation and parasitic infection in a patient with normochromic normocytic anemia and eosinophilia, and can iron deficiency anemia be considered if ESR and CRP are normal?

Evaluation of Normochromic Normocytic Anemia with Eosinophilia and Suspected Parasitic Infection

CBC, ESR, CRP, and stool examination for ova and parasites are essential tests for evaluating normochromic normocytic anemia with eosinophilia, but additional iron studies (serum ferritin, transferrin saturation) are required to rule out iron deficiency even if inflammatory markers are normal.

Diagnostic Approach for Normochromic Normocytic Anemia with Eosinophilia

Initial Laboratory Assessment

• Complete Blood Count (CBC) findings:
  • Hemoglobin 9.7 g/dL (indicating moderate anemia)
  • Normal WBC count
  • Eosinophilia on peripheral smear
  • Normochromic normocytic RBC morphology

This presentation requires a systematic evaluation to determine the underlying cause:

1. Inflammatory markers: ESR and CRP are important but not sufficient alone 1
2. Iron studies: Even with normochromic normocytic anemia, iron deficiency must be evaluated 1, 2
3. Stool examination: Essential for detecting parasitic infections 3, 4

Iron Deficiency Evaluation

Even with normochromic normocytic presentation, iron deficiency should be considered for several reasons:

• Iron deficiency can initially present as normocytic before developing microcytosis 2
• Normal ESR and CRP do not exclude iron deficiency 1
• The combination of parasitic infection and iron deficiency can occur, especially with intestinal parasites causing blood loss 4

Required Iron Studies

The minimum iron workup should include:

• Serum ferritin
• Transferrin saturation
• Serum iron
• Total iron binding capacity (TIBC)

According to guidelines, serum ferritin <30 μg/L without inflammation indicates iron deficiency, while values up to 100 μg/L may still represent iron deficiency in the presence of inflammation 1.

Parasitic Infection Assessment

Eosinophilia strongly suggests a tissue-invasive helminthic infection 3, 4:

• Absolute eosinophil count >500/μL indicates eosinophilia
• Eosinophilia is particularly pronounced in co-infection with intestinal helminths and ectoparasites 4
• Stool examination for ova and parasites has high diagnostic value but may require multiple samples 3

Research shows eosinophilia correctly predicts parasitic infection in 87% of cases in endemic areas 4.

Interpretation of Normal Inflammatory Markers

If ESR and CRP are normal:

• This does not exclude iron deficiency anemia 1
• It makes anemia of chronic disease less likely 1, 5
• It does not rule out parasitic infection 4

Diagnostic Algorithm

1. First tier testing:

   • CBC with peripheral smear review
   • ESR and CRP
   • Stool examination for ova and parasites (multiple samples)
   • Iron studies (ferritin, transferrin saturation, iron, TIBC)

2. Second tier testing (if diagnosis remains unclear):

   • Reticulocyte count to assess bone marrow response 1
   • Vitamin B12 and folate levels
   • Serology for specific parasites based on geographic prevalence
   • Haptoglobin, LDH, and bilirubin to rule out hemolysis 1, 5

Common Pitfalls to Avoid

1. Assuming normal ESR/CRP excludes iron deficiency - Iron deficiency can occur with normal inflammatory markers 1, 2

2. Relying on a single stool sample - Multiple stool examinations may be necessary due to intermittent shedding of parasites 3

3. Overlooking mixed causes of anemia - Parasitic infection and iron deficiency can coexist, especially with intestinal parasites causing blood loss 4

4. Focusing only on parasites with eosinophilia - While eosinophilia strongly suggests parasitic infection, a comprehensive anemia workup is still needed 1

In conclusion, while CBC, ESR, CRP, and stool examination provide valuable information, they are insufficient alone to fully evaluate normochromic normocytic anemia with eosinophilia. Iron studies are essential even with normal inflammatory markers to rule out iron deficiency, which can coexist with parasitic infection.