| Primary Name |
Anti-Xa |
| Synonym |
Unfractionated heparin anti-Xa assay |
| Synonym |
Low molecular weight heparin anti-Xa assay |
| Contraction |
Heparin assay |
| Contraction |
UFH anti-Xa assay |
| Contraction |
LMWH anti-Xa assay |
| UAB Procedure Number |
2500670 |
| CPT Code |
85520 |
| Specimen |
Collect one (1) blue-stopper tube (3.2% sodium citrate), filled to specified volume. Do not underfill or overfill. |
| Specimen Management |
Centrifuge blue-stopper tube within one (1) hour of collection, separate plasma and test or quick-freeze at -70°C. |
| Specimen Accepted |
Daily including weekends |
| Times Available |
0730-1600; deliver to lab by 1300 for same-day results |
| Test Performed |
Monday-Friday |
| Available Stat? |
Pathologist's approval required. |
| Description |
The anti-Xa test is the most accurate assay for monitoring unfractionated heparin therapy and is the only assay available for monitoring low molecular weight heparin (Lovenox®). The anti-Xa level applies to patients anticoagulated with heparins (unfractionated and low molecular weight heparin). |
| Reference Interval |
0.0 anti-Xa heparin units per mL plasma. |
| Critical Value |
-- |
| Therapeutic Range |
*IV therapeutic unfractionated heparin: 0.4 - 0.7 anti-Xa units per mL plasma.
*Prophylactic unfractionated heparin: 0.1-0.4 anti-Xa units per mL plasma.
*Low molecular weight heparin (Lovenox, enoxaparin): 0.5 to 1.0 anti-Xa units per mL plasma for therapy when injected twice a day. Draw four hours after injection.
*Low molecular weight heparin (Lovenox, enoxaparin): 1.0 to 2.0 anti-Xa units per mL plasma for therapy when injected once a day. Draw four hours after injection.
*Low molecular weight heparin (Lovenox, enoxaparin): 0.2 to 0.4 anti-Xa units per mL plasma for prophylaxis. Draw four hours after injection. |
| Follow-up Test |
-- |
| Associated With |
Heparin therapy |