Haematology — White Cell & Inflammatory Ratios

Turn a white cell count and an eosinophil percentage into the absolute eosinophil count, and read it against the thresholds that actually define eosinophilia and hypereosinophilia.

Turn a white cell count and a lymphocyte percentage into the absolute lymphocyte count, and read a low result properly — most lymphopenia is transient, and the count that stays down is the one that needs a cause.

Turn a white cell count and a monocyte percentage into the absolute monocyte count — and see why 0.5 ×10⁹/L now matters even though it sits inside the reference interval.

Convert a white cell count and differential into the absolute neutrophil count, and read the neutropenia bands correctly.

Automated analysers count nucleated red cells as white cells, so a marrow-stressed sample reports a falsely high WBC. Correct it here — and correct it before any absolute neutrophil count is derived.

Calculate the lymphocyte-monocyte ratio — and read the honest caveat with it. There is no reference interval and no agreed cut-off; every published threshold was chosen from a single study’s own data.

Grade neutropenia by absolute neutrophil count. First, the thing that matters more than the grade: a temperature of 38.3 °C once, or 38.0 °C for over an hour, with a neutrophil count below 0.5 ×10⁹/L is a medical emergency needing antibiotics within one hour.

Calculate the neutrophil-lymphocyte ratio and read it as what it is — a broad stress marker, not a specific diagnostic test.

Calculate the platelet-lymphocyte ratio, another broad inflammatory marker with the same caveats as NLR.

Calculate SII from platelets, neutrophils and lymphocytes — and see why no single cut-off applies across conditions.

Convert a white cell count between ×10⁹/L, ×10³/µL, K/µL, cells/µL and cells/mm³ — and see why a normal total is not the reassurance it looks like.