Full blood count and blood-film interpretation in children — structured clinical encounter

Structured encounter testing the interpretation of a paediatric full blood count: a printout that must be read against age-specific ranges, the physiological anaemia of infancy, the mean-cell-volume sort of a microcytic anaemia with iron dosing and the thalassaemia distinction, a child with isolated thrombocytopenia, an EDTA artefact, and a film that demands urgent oncology review.

structured clinical encounter3 min readVerification in progress

Prompt

You are the paediatric registrar in clinic and the emergency department. Across the encounter you interpret a full blood count that lands on your screen, with the age and the values released in stages: a thriving infant at the physiological nadir, a toddler with microcytic anaemia and a heavy milk intake, a four-year-old with isolated thrombocytopenia after a viral illness, a well child with a platelet count that does not fit the picture, and finally a film with blasts and pancytopenia that demands an urgent pathway.

Station 1 — the printout that needs an age

Asked for my first move on a haemoglobin of 100, I would say I cannot interpret a paediatric value without the age band, because the same number is normal at the physiological nadir of infancy and abnormal in an older child. I would state the age aloud and read every value against age-specific paediatric reference intervals, not adult ranges, and I would read the blood film alongside the count. [1] [4]

Paediatrics Fellowship Pro

You have read the opening of this case. The complete unit — every section and its primary-source references — is part of the Paediatrics Fellowship fellowship atlas.

References7Show ledger

[1]Adeli K; Higgins V; Seccombe D; et al The Canadian laboratory initiative on pediatric reference intervals: A CALIPER white paper. Crit Rev Clin Lab Sci, 2017.PMID 29017389
[4]Celkan TT What does a hemogram say to us? Turk Pediatri Ars, 2020.PMID 32684755
[5]Raleigh MF; Chaffin M; O'Connor K Anemia in Infants and Children: Evaluation and Treatment. Am Fam Physician, 2024.PMID 39700365
[6]Wang M Iron Deficiency and Other Types of Anemia in Infants and Children. Am Fam Physician, 2016.PMID 26926814
[8]Courville EL; et al Performance of Automated Hematology Analyzer Criteria in Detecting Peripheral Blood Smear Abnormalities: A Systematic Literature Review. Int J Lab Hematol, 2026.PMID 42115681
[9]Neunert C; Terrell DR; Arnold DM; et al American Society of Hematology 2019 guidelines for immune thrombocytopenia. Blood Adv, 2019.PMID 31794604
[10]Rose-Inman H; Farmen J Acute leukemia. Emerg Med Clin North Am, 2014.PMID 25060251