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HelpTest Code SCT Silica Clotting Time (SCT)
Synonyms/Keywords
PTT-LA, Lupus Anticoagulant PTT
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | *Platelet Poor Citrated Plasma | Citrated Blue Top Tube (BTT) | 0.75 mL | 0.75 mL | 0.5 mL |
Collection/Processing Instructions
One 0.75 mL citrated Blue Top Tube (BTT) plasma aliquot. (If more than one coagulation test is ordered, a separate aliquot is needed for each test.)
- Collect in Citrated Blue Top Tube (BTT)
- Citrate anticoagulant must be adjusted for HCT >55%
- Tube must be at least 90% full
- Invert completely 3-4 times (without shaking) to mix
*See Instructions for: Preparation of Platelet Poor Plasma
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma | Room Temp | 4 hours |
| Refrigerated | 4 hours | |
| Frozen (-70) | 6 months |
Rejection Criteria
Clotted or Hemolyzed sample
Contamination with IV or Hickman Line fluids
Specimens that thaw during storage or transport
Test Components
SCT ratio
Test Information
To increase the sensitivity and specificity of the laboratory diagnosis of lupus anticoagulants (LA) both the DRVVT and the SCT should be ordered. These two tests have been combined as a Lupus Anticoagulant Panel (LAPAN) test order.
Lupus anticoagulant testing (DRVVT and SCT) should not be performed on patients receiving rivaroxaban, apixaban, dabigatran, or warfarin. For patients on these medications, one may consider anticardiolipin antibody and/or anti-beta-2 glycoprotein 1 antibody testing.
See Lab Clinical Practice Guidlines: Hypercoagulability for more information
Reference Range Information
SCT ratio: ≤1.16 Negative for LA
SCT ratio: >1.6 Positive for LA
Marshfield Labs Performing Department
Marshfield Labs Coagulation
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time |
Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday, Wednesday, Friday | Less than 2 hours | ACL TOP 550 |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 85732 | Optical Clot Detection |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 85732 | Optical Clot Detection |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | Silica Clotting Time |