Clinical Relevance
Apixaban is a direct inhibitor of activated factor X (FXa) and is given orally for the prophylaxis of a range of conditions including VTE in adults after hip or knee replacement surgery, recurrent DVT, and stroke in patients with non-valvular atrial fibrillation.
Apixaban does not require routine anticoagulant monitoring but measurement would be required in certain clinical situations where the result will alter management, including prior to emergency surgery or when bleeding.
Reference range
Expected levels 3-hours post dose on patients taking ‘therapeutic’ doses of the drug:
VTE Prophylaxis
| Apixaban Dose | Observed Peak Conc. | Observed Trough Conc. |
|---|---|---|
| 2.5mg bid | 41 – 146 ng/ml | 23 – 109 ng/ml |
VTE Treatment
| Apixaban Dose | Observed Peak Conc. | Observed Trough Conc. |
|---|---|---|
| 2.5mg bid | 30 – 153 ng/ml | 11 – 90 ng/ml |
| 5mg bid | 56 – 302 ng/ml | 22 – 177 ng/ml |
| 10mg bid | 111 – 572 ng/ml | 41 – 335 ng/ml |
Stroke Prevention in AF
| Apixaban Dose | Observed Peak Conc. | Observed Trough Conc. |
|---|---|---|
| 2.5mg bid | 69 – 221 ng/ml | 34 – 162 ng/ml |
| 5mg bid | 91 – 321 ng/ml | 41 – 230 ng/ml |
Min. Volume
The volume of blood in coagulation samples must lie within the volume range as indicated by the size of the black fill arrow present on tubes. Volumes above or below the arrow will result in sample rejection to ensure validity of results.
Turnaround Time
4 hours
Age of Sample
Samples will be rejected if received more than 1 hours post venepuncture.
Specimen Requirements
- 2 blue top (sodium citrate) samples
- all coagulation tubes must be adequately filled (see above)
- All coagulation tubes must be mixed several times by gentle inversion immediately after venepuncture. Mixing the sample the anticoagulant stops the sample clotting within the tube.
Limitations
- It is not possible to provide results on clotted, insufficient, lipaeamic or haemolysed samples. These samples will be rejected with the appropriate comment.
- Samples tubes that have expired cannot be accepted
Analysing Laboratory
Coagulation (JCUH)