Laboratory Workup for Patient with Hemoglobin of 8.6
For a patient with severe anemia (hemoglobin 8.6 g/dL), a comprehensive laboratory workup should include complete blood count with reticulocyte count, iron studies (serum ferritin, transferrin saturation), vitamin B12 and folate levels, and assessment for occult blood loss. 1, 2
Initial Laboratory Evaluation
Complete Blood Count (CBC) with differential
- Provides information on red cell indices (MCV, MCH, MCHC)
- Helps classify anemia as microcytic, normocytic, or macrocytic
- Evaluates white blood cell and platelet counts to assess for other hematologic abnormalities
Reticulocyte Count
- Assesses bone marrow response to anemia
- Low count suggests inadequate production
- High count suggests hemolysis or blood loss
Iron Studies
- Serum ferritin (tissue iron stores)
- Transferrin saturation (iron available for erythropoiesis)
- Serum iron and total iron binding capacity (TIBC)
- Consider percent hypochromic red blood cells if available
Vitamin B12 and Folate Levels
- Essential for ruling out nutritional deficiencies
- Particularly important if macrocytic anemia is present
Additional Testing Based on Clinical Context
Occult Blood Testing
- Stool guaiac test to evaluate for gastrointestinal blood loss
- Particularly important in patients with iron deficiency
Renal Function Tests
- Serum creatinine and eGFR
- Anemia is common when GFR falls below 60 mL/min/1.73m² 2
Inflammatory Markers
- C-reactive protein (CRP)
- Erythrocyte sedimentation rate (ESR)
- Helps assess for anemia of chronic disease/inflammation
Hemolysis Evaluation (if clinically indicated)
- Lactate dehydrogenase (LDH)
- Haptoglobin
- Direct Coombs test
Specialized Testing When Indicated
Thyroid Function Tests
- Hypothyroidism can cause normocytic, normochromic anemia 1
Bone Marrow Examination
- Consider if diagnosis remains unclear after initial workup
- Particularly important if multiple cell lines are affected
Hemoglobin Electrophoresis
- If hemoglobinopathy is suspected based on ethnicity or family history
Interpretation and Follow-up
The classification of anemia based on MCV is crucial for directing further evaluation:
- Microcytic (low MCV): Consider iron deficiency, thalassemia, or anemia of chronic disease
- Normocytic (normal MCV): Consider anemia of chronic disease, renal disease, or early deficiency
- Macrocytic (high MCV): Consider vitamin B12/folate deficiency or medication effects 2
Monitoring Recommendations
- Monitor hemoglobin every 2-4 weeks initially, then monthly once stable
- Reassess iron status every 3 months during treatment
- Regular monitoring of renal function if chronic kidney disease is present
Common Pitfalls to Avoid
- Overlooking occult blood loss as a cause of anemia
- Assuming anemia is solely due to a single cause without complete evaluation
- Inadequate iron replacement despite evidence of deficiency
- Failing to monitor response to therapy
Remember that severe anemia (Hb <8.0 g/dL) as seen in this patient requires thorough evaluation before attributing it to a single cause 1.
Transfusion Considerations
While arranging workup, consider that restrictive transfusion thresholds (Hb 7-8 g/dL) are generally recommended for hemodynamically stable patients, but clinical context and patient symptoms should guide transfusion decisions 3.
The comprehensive laboratory evaluation outlined above will help determine the underlying cause of the patient's anemia and guide appropriate treatment strategies.