Circulating Inhibitor against Factor X: A Rare Cause of Hemorrhagic Diathesis

Table 1

Coagulation and hematological values on hospital admission.

Parameters	Laboratory results	Reference intervals
Hemoglobin (g/dl)	15.2	13–17
White blood cell (×10^9/L)	6.0	4.0–10.0
Platelet count (×10^9/L)	180	150–400
PT value (%)^†	18	70–110
INR	4.55	0.8–1.20
PT (s)^†	39.9	MNPT of 12.5^‡
aPTT (s)	83.4	28–42
Thrombin time (s)	16.4	14–25
Fibrinogen (mg/dL)	386	150–400
D-dimer (mg/L FEU)^§	0.28	0–0.50
Coagulation factor assays^||
Factor II (%)	62	50–150
Factor V (%)	91	50–150
Factor VII (%)	71	50–150
Factor VIII (%)	111	50–150
Factor IX (%)	121	50–150
Factor X (%)	18	50–150
Factor XI (%)	123	50–150
Factor XII (%)	82	50–150

Analyzers used in this hospital’s laboratory are as follows: XE-5000 (Sysmex) for complete blood count, STA-R Evolution (Stago) for routine coagulation testing, and ACL TOP 500 (Werfen/Instrumentation Laboratory) for coagulation factors. ^†Note that when using the STA-R Evolution (Stago) analyzer, a PT value expressed in % is obtained, representing the patient’s coagulation time relative to the standardized coagulation times of control samples. To provide a more representative measurement, PT value in seconds (39.9) has been reported and can be compared to the MNPT (mean normal prothrombin time) value of the lab (12.5), for this lot of thromboplastin reagent. The reagent lot used for the PT determination was STA Neoplastine CI Plus 5 250576 (International Sensitivity Index (ISI) of 1.30). ^‡MNPT represents the average prothrombin time of healthy individuals and serves as a reference for comparison for calculation of INR. ^§Reagent used for D-dimer was STA Liatest DDi (Stago). Regarding the reference interval, 0.50 represents the cutoff value, with values greater than 0.50 mg/L FEU not supporting the exclusion of venous thromboembolism. ^||For the determination of factor activities, the following reagents were used. PT reagent: HemosIL RecombiPlasTin (factors II, V, VII, and X). aPTT reagent: HemosIL SynthASil (factors VIII, IX, XI, and XII). These were utilized on an ACL TOP 500 automated coagulation analyzer (Werfen/Instrumentation Laboratory).