Test Details
Methodology
F 1+2 is measured by an enzyme immunoassay based on the sandwich principle.6 F 1+2 in the sample binds to anti-F 1+2 antibodies fixed to the microtiter plate during an incubation period. Peroxidase conjugated antibodies are then added and a second incubation takes place. A chromophore is added and color formation is directly proportional to the concentration of F 1+2.
Result Turnaround Time
3 - 9 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Evaluation of F 1+2 in plasma is a determinant of in vivo thrombin generation.
Limitations
Traumatic venipuncture or prolonged stasis may invalidate results.6 Improper mixing of the specimen after venipuncture can falsely elevate F 1+2 levels.
Custom Additional Information
Prothrombin fragment 1+2 (F 1+2) is the amino terminus fragment of the prothrombin molecule. It is a polypeptide with a half-life of approximately 90 minutes.6 F 1+2 is released from prothrombin when prothrombin is converted to thrombin by the prothrombinase complex. The prothrombinase complex consists of activated factors X and V, calcium ions, and phospholipid. F 1+2 has been utilized to assess thrombotic risk and monitor anticoagulant therapy. Increases of F 1+2 occur as a result of increased conversion of prothrombin to thrombin. F 1+2 levels are elevated in patients with deep vein thrombosis, pulmonary embolism, disseminated intravascular coagulation, septicemia, preëclampsia, eclampsia, and trauma. F 1+2 is elevated as much as two times normal in patients with antithrombin deficiency. F 1+2 is decreased below the reference range in patients undergoing oral anticoagulant therapy and levels may be used to assess efficacy of anticoagulant therapy. F 1+2 may be accompanied by increases in other markers of clot formation and lysis such as fibrinopeptide A, thrombin-antithrombin complex, and D-dimer.
Specimen Requirements
Specimen
Plasma, frozen
Volume
2 mL
Minimum Volume
1 mL
Container
Blue-top (sodium citrate) tube
Collection Instructions
Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples.4,5 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge and carefully remove the plasma using a plastic transfer pipette, being careful not to disturb the cells. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Storage Instructions
Freeze; three freeze/thaw cycles are acceptable. Stable at room temperature or refrigerated for four hours.
Patient Preparation
Do not draw from an arm with a heparin lock or heparinized catheter.
References
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 500016 | Prothrombin Fragment 1+2 MoAb | 500789 | Prothrombin Fragment 1+2 MoAb | pmol/L | 27824-2 | |
| Order Code | 500016 | |||||
| Order Code Name | Prothrombin Fragment 1+2 MoAb | |||||
| Order Loinc | ||||||
| Result Code | 500789 | |||||
| Result Code Name | Prothrombin Fragment 1+2 MoAb | |||||
| UofM | pmol/L | |||||
| Result LOINC | 27824-2 |