A normal screen, a real bleeding history

An adult outpatient reports recurrent epistaxis, heavy menstrual bleeding, and prolonged bleeding after a dental extraction. No deep muscle or joint bleeding is reported. The coagulation panel comes back: platelet count 248 x10^9/L (reference interval 150-400 x10^9/L), PT 11.8 s (10.5-13.5 s), aPTT 31.2 s (25.0-35.0 s), and Clauss fibrinogen 286 mg/dL (200-400 mg/dL). The citrate tube is full and unclotted, drawn by peripheral venipuncture, and no analyzer flags are present. Ibuprofen use is reported during menses, and there is no anticoagulant exposure.

Every number on this panel sits inside its reference interval. A first read might close the case as normal hemostasis, but the bleeding history says otherwise: mucocutaneous bleeding at more than one site, provoked and spontaneous, is not explained away by a normal PT, aPTT, and platelet count. The question is how platelet count, PT, aPTT, fibrinogen, and history work together to organize the initial differential and choose what to test next, not how to name a final diagnosis from four screening numbers.

Rule out a specimen or medication look-alike, weigh the history against the numbers, sort a result set into a small number of recognizable patterns, and select one defensible next laboratory action.

A normal coagulation screen narrows the differential, it does not close it, and the history tells you where to look next.