| Ordering Code | 8449 |
|---|---|
| Test Name | Lupus Anticoagulant SCT w/ Interp |
| Alias | APTT-based LA LA Profile Silica LAC Screen |
| Preferred Specimen | Plasma |
| Preferred Container | Citrate, 3.2% (Lt Blue) |
| Other Specimen/Container | Whole Blood in Citrate, 3.2% (Lt Blue) if testing is done within 4 hours. |
| Optimum Volume | Aliquoted Plasma: 2 mL (2 tubes) |
| Collection Instructions | Draw 2 tubes, Full draw Mix tube well This assay should not be ordered in patients receiving anticoagulant therapy. Anticoagulants including direct oral agents (such as Factor Xa and Thrombin inhibitors), UFH and LMWH--can mask or mimic pathological findings. Testing under these conditions significantly compromises the validity of assay interpretation. |
| Handling Instructions | Double centrifuge to produce platelet-poor plasma, avoid the WBC/platelet buffy layer, separate and freeze at -20 deg C immediately. Do NOT thaw once specimen is frozen. |
| Transport Requirements | Preferred method of transport is frozen plasma. |
| Specimen Stability | Ambient: 4 Hours Frozen: 2 Weeks Plasma |
| Rejection Criteria | Clotted, Contaminated, Hemolyzed, Improperly filled or underfilled tube, Collected in the wrong anticoagulant, Mislabeled, Specimen older than stability limits |
| Avail. Stat | NO |
| Analytic Time | Up to 5 Days |
| Methodology | Clot Detection |
Reference range(s)
The reference ranges listed below are valid on this date of May 22, 2026.
| Component | Age | Male Norm | Male Critical Low | Male Critical High | Female Norm | Female Critical High | Female Critical Low | Units | Add'l info |
|---|---|---|---|---|---|---|---|---|---|
| Protime | ALL | 10.2-12.9 | 10.2-12.9 | secs | |||||
| Part. Throm. Time (PTT) | ALL | 25.1-36.5 | >= 200.1 | 25.1-36.5 | >= 200.1 | secs | |||
| Thrombin Time | ALL | 10.3-16.6 | 10.3-16.6 | secs | |||||
| Anti-Xa | ALL | <=0.07 | <=0.07 | IU/mL | |||||
| SCT S Ratio | ALL | <=1.23 | <=1.23 | ||||||
| SCT C Ratio | ALL | See report. | |||||||
| SCT Normalized Ratio | ALL | <=1.13 | <=1.13 | ||||||
| SCT S Mix Ratio | ALL | See report. |