Diagnosing congenital deficiencies (rare) of coagulation factor V
Evaluating acquired deficiencies associated with liver disease, factor V inhibitors, myeloproliferative disorders, and intravascular coagulation and fibrinolysis
Investigation of prolonged prothrombin time or activated partial thromboplastin time
Specimen Type
Platelet-Poor-Plasma (Citrated)
Specimen Requirements
Light-blue top (3.2% sodium citrate)
Specimen Collection / Processing Instructions
Patient must not be receiving Coumadin or heparin therapy
Specimen must be collected prior to factor replacement therapy
Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again
Aliquot plasma into a plastic vial, leaving 0.25 mL in the bottom of centrifuged vial
Freeze plasma immediately (no longer than 4 hours after collection) at -20^C or, ideally, ≤ -40^C
Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results
Each coagulation assay requested should have its own vial.
Stability
Frozen 14 days
Unacceptable Specimen Conditions
Gross hemolysis
Gross lipemia
Gross icterus
Limitations
Coagulation testing is highly complex, often requiring the performance of multiple assays and correlation with clinical information. For that reason, consider ordering a Coagulation Consultation.
Factor V (labile factor) is highly susceptible to proteolytic inactivation, with the potential for spuriously decreased assay results. In normal individuals, after freeze-thaw of citrate plasma, factor V activity typically may be 10% to 20% less than observed in a fresh plasma specimen, and in occasional individuals, a more marked decrease of factor V activity occurs. Normal results can be regarded as reliable, but decreased factor V activity results need to be correlated with other clinical and laboratory information. Repeat testing may be necessary.
Methodology
Optical Clot-Based
Estimated TAT
1-2 days
Testing Schedule
Monday-Friday
Retention
7 days
CPT Code(s)
85220
Reference Range
> 1 month old: 70-165% < 1 month old: Normal, full-term newborn infants may have mildly decreased levels (≥ 30% to 35%) which reach adult levels within 21 days
