Anemia, Red Cell Disease and Hematologic Diagnostic Reasoning

Course 03: Cardiovascular, Vascular and Hematology

Lesson 10 of 12. Read the diagnostic framework and case, then complete the 10-question practice set. All material is original educational content; high-risk presentations require emergency referral.

CBC and reticulocyte approach

Classify anemia by MCV: microcytic, normocytic and macrocytic; confirm clinical severity and symptoms.
Use reticulocyte response to differentiate underproduction from destruction or blood loss, alongside smear and relevant clinical information.
Consider iron status, B12, folate, renal function, inflammation, hemolysis indices and bleeding history as directed by the differential.
CBC reference intervals vary with age, pregnancy and laboratory; trends may be more informative than one isolated value.

Microcytic and iron deficiency

Low ferritin supports iron deficiency, but ferritin may be falsely elevated with inflammation; transferrin saturation can help in context.
Common microcytic causes include iron deficiency, thalassemia trait and anemia of inflammation.
Investigate cause of iron deficiency, particularly GI bleeding in appropriate risk groups; iron replacement without etiology workup may miss pathology.
Thalassemia trait may show marked microcytosis with relatively preserved RBC count; avoid labeling it iron deficiency without iron studies.

Macrocytic and normocytic anemia

Macrocytosis may reflect B12 or folate deficiency, alcohol, liver disease, hypothyroidism, reticulocytosis or marrow pathology.
Neurological signs suggest B12 deficiency; do not correct folate alone while failing to recognize B12-related neuropathy.
Normocytic anemia includes acute blood loss, inflammation, renal disease, marrow disease or early iron deficiency.
Consider hematology referral for unexplained cytopenias or abnormal smear/blasts.

Hemolysis and urgent findings

Hemolysis pattern includes increased LDH and indirect bilirubin, low haptoglobin and reticulocytosis when marrow response is intact.
Schistocytes with thrombocytopenia or renal/neuro abnormalities raises concern for microangiopathic hemolytic anemia needing urgent evaluation.
Severe symptomatic anemia with syncope, chest pain, hemodynamic instability or active bleeding requires emergency assessment.
Transfusion decisions depend on symptoms, comorbidity and institutional protocols, not hemoglobin alone.

Communication and follow-up

Explain uncertainty when ferritin, inflammation and renal function produce mixed patterns.
Communicate follow-up tests, response to replacement and indications to pursue bleeding sources.
Document red-flag symptoms and escalation thresholds based on the clinical picture.

Applied clinical case

A 58-year-old reports fatigue; Hb 89 g/L, MCV 70 fL, ferritin 8 micrograms/L and no obvious menstrual source.

Show model clinical reasoning and disposition

Iron deficiency anemia is likely; evaluate possible blood loss including gastrointestinal sources as appropriate and address symptoms and iron replacement with clinician follow-up.