Module overview
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Opening laboratory problem

This case involves a 30-month-old child and uses a venous EDTA CBC, ferritin, C-reactive protein, reticulocyte hemoglobin equivalent (Ret-He), a smear review, and blood-lead testing. Compare each result with the stated local pediatric interval and the reported specimen type before assigning meaning.

The complete case dataset appears once in the table below. It establishes anemia with microcytosis and a differential pattern; it does not establish a genotype, cause of anemia, or lead toxicity.

The immediate laboratory decisions are whether age-specific comparison identifies anemia or microcytosis, whether marrow response is appropriate, whether the CBC pattern merits smear review, whether collection failure requires rejection or recollection, and what follow-up or report wording is required.

Select the child's exact age partition and specimen type before attaching clinical meaning to a result.

Illustrative drawing — this picture was drawn rather than captured.

Categorical display showing low hemoglobin and MCV, low ferritin, non-elevated CRP, and a capillary lead screen that requires venous confirmation; it does not show Ret-He or a diagnostic ranking.
Figure 1Categorical display of the pediatric case before differential ranking.
Complete case data for a 30-month-old child
Test or observationResultLocal pediatric interval or flagInterpretive role
Hemoglobin9.8 g/dL10.8–13.5 g/dLLow: anemia for the stated age partition
MCV66 fL72–86 fLLow: microcytosis
Red blood cells4.78 × 10^12/L3.90–5.30 × 10^12/LWithin interval; does not exclude a hemoglobinopathy
RDW17.8%11.5–14.5%High: increased red-cell size variation
Platelets468 × 10^9/L150–450 × 10^9/LMildly high; interpret with the full pattern
Absolute reticulocytes (ARC)42 × 10^9/L30–90 × 10^9/LWithin interval; not an increased regenerative response
Smear reviewMicrocytosis, hypochromia, anisocytosis; no basophilic stipplingMorphology reviewSupports pattern review; stippling absence is not a lead test
Ferritin9 micrograms/L12–200 micrograms/LLow store marker
C-reactive protein0.4 mg/Lbelow 5 mg/LCRP was not elevated at collection
Ret-He24 pg27–33 pgLow by this locally validated method
Capillary blood lead4.2 micrograms/dLAt or above CDC BLRV 3.5 micrograms/dLScreen requiring venous confirmation
Venous whole-blood lead2.1 micrograms/dLConfirmed venous resultReport as venous; do not infer the capillary result’s source

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Knowledge check 1

Which comparison must precede interpretation of this child’s CBC?

Choose one option.

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The module finishes after every required section is marked done and every check in those sections is correct.