Oral Contraceptive/Hormone Replacement Therapy Thrombotic Risk
| Oral Contraceptive/Hormone Replacement Therapy Thrombotic Risk | | | |
| Number | | 336574 |
| CPT | | 83891; 83892; 83894 (x2); 83898 (x3); 83912 (x2); 85300; 85303; 85306 |
| Test Includes | | Antithrombin activity; factor II (prothrombin) mutation analysis; factor VLeiden mutation analysis; protein C, functional, protein S antigen, free |
| Specimen | | Plasma, frozen, whole blood, or buccal swab kit (buccal swab collection kit contains instructions for the use of a buccal swab) |
| Volume | | 4 mL plasma, frozen (2 mL in each of two tubes), 7 mL whole blood, or LabCorp buccal swab kit |
| Container | | Blue-top (sodium citrate) tube, lavender-top (EDTA) tube, yellow-top (ACD) tube, or LabCorp buccal swab kit |
| Collection | | 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. |
| Storage Instructions | | Freeze plasma. Maintain whole blood and buccal swab kit at room temperature or refrigerate. |
| Patient Preparation | | Do not draw from an arm with a heparin lock or heparinized catheter. |
| Methodology | | See individual tests. |
| Footnotes | | - Adcock DM, Kressin DC, and Marlar RA, “Effect of 3.2% vs 3.8% Sodium Citrate Concentration on Routine Coagulation Testing,” Am J Clin Pathol, 1997, 107(1):105-10.
- Reneke J, Etzell J, Leslie S, et al, “Prolonged Prothrombin Time and Activated Partial Thromboplastin Time Due to Underfilled Specimen Tubes With 109 mmol/L (3.2%) Citrate Anticoagulant,” Am J Clin Pathol, 1998, 109(6):754-7.
- “National Committee for Clinical Laboratory Standardization: Collection, Transport, and Processing of Blood Specimens for Coagulation Testing and General Performance of Coagulation Assays; Approved Guideline,” Third Edition, Villanova: NCCLS Document H21-A3:11(23), 1999.
- Gottfried EL and Adachi MM. “Prothrombin Time and Activated Partial Thromboplastin Time Can Be Performed on the First Tube,” Am J Clin Pathol, 1997, 107(6):681-3.
- McGlasson DL, More L, Best HA, et al, “Drawing Specimens for Coagulation Testing: Is a Second Tube Necessary?” Clin Lab Sci, 1999, 12(3):137-9
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