Prekallikrein (Fletcher Factor) Assay
Also known as: Fletcher Factor Assay
Use
Measurement of prekallikrein factor concentration
Special Instructions
Citrated plasma samples should be collected by double centrifugation. Blood collection should be in a blue-top tube with 3.2% buffered sodium citrate. Proper blood to anticoagulant ratio must be ensured by filling collection tubes completely. Samples need to be handled gently during mixing. Immediate freezing after centrifugation is essential to maintain specimen integrity. Separate frozen specimens are required if multiple tests are requested to avoid delays in turnaround time.
Limitations
Prekallikrein deficiency itself does not lead to bleeding, but it can prolong aPTT results in a laboratory setting. Deficiencies of factor XII, prekallikrein, and high molecular weight kininogen are included in this category, with generally no clinical evidence of bleeding unless other contributing factors are present. Diagnoses are typically made when aPTT is prolonged without an evident cause, excluding any bleeding disorder.
Methodology
Other
Biomarkers
LOINC Codes
- 52759-8
- 52759-8
Result Turnaround Time
4-8 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
2 mL
Minimum Volume
1 mL
Container
Blue-top (sodium citrate) tube
Collection Instructions
Blood must be drawn in a blue-top tube containing 3.2% buffered sodium citrate. After drawing, gently invert the tube at least six times to mix blood with the anticoagulant. Centrifuge for 10 minutes and collect 2/3 of the plasma, centrifuge again, and transfer plasma to a Labcorp PP transpak frozen purple tube; freeze immediately. Submit separate frozen specimens for each test requested when multiple tests are ordered.
Patient Preparation
Do not draw from an arm with a heparin lock or heparinized catheter.
Storage Instructions
Freeze. Stable at room temperature for four hours.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 hours |