What does the White Blood Cell Count with 5-Part Automated Differential test measure?

Why is White Blood Cell Count with 5-Part Automated Differential measured?

The WBC total count and 5-part differential is the primary haematological screen for infectious, inflammatory, allergic, immunological, and haematoproliferative conditions. Absolute neutrophil count (ANC) is the critical safety threshold for infection risk in immunocompromised patients. Absolute lymphocyte count (ALC) is the primary immune competence marker in HIV monitoring and post-chemotherapy recovery assessment. The neutrophil-to-lymphocyte ratio (NLR) is a validated prognostic marker across cardiovascular disease, malignancy, sepsis, and inflammatory conditions — rising NLR indicates a shift toward innate immune predominance consistent with systemic inflammatory activation. Eosinophilia directs investigation toward atopic disease, parasitic infection, drug reactions, or — at higher counts — eosinophilic granulomatosis with polyangiitis and eosinophilic leukaemia.

Reference ranges

Standard reference

WBC Total: 4.5–11.0 ×10³/µL; Neutrophils: 45–75% (1.8–7.7 ×10³/µL); Lymphocytes: 16–45% (0.9–5.2 ×10³/µL); Monocytes: 4–11% (0.2–0.9 ×10³/µL); Eosinophils: 0–8% (0.0–0.7 ×10³/µL); Basophils: 0–3% (0.0–0.2 ×10³/µL) # REVIEWER FLAG: Confirm Quest Diagnostics reference ranges for WBC total and all differential sub-components — values are age-stratified in paediatric populations and may differ from adult reference ranges. Verify absolute count reference intervals against Quest's current platform documentation, as these differ materially from the percentage ranges and are more clinically actionable.

Functional medicine optimal

WBC Total: 4.5–7.5 ×10³/µL (functional medicine optimal for minimal chronic inflammatory burden — lower WBC within the reference range is associated with reduced ASCVD risk in population cohorts); NLR: <2.0 (systemic inflammatory wellness target). # REVIEWER FLAG: NLR optimal threshold is based on emerging population health literature — not a standardised clinical guideline target. Confirm whether Quest Diagnostics reports NLR as a derived value on the CBC report or whether it must be calculated independently.

Units

WBC: ×10³/µL, Neutrophils: % and ×10³/µL, Lymphocytes: % and ×10³/µL, Monocytes: % and ×10³/µL, Eosinophils: % and ×10³/µL, Basophils: % and ×10³/µL

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.