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HelpTest Code Billings Clinic: 8198 Heparin Assay, Plasma
Performing Laboratory
Billings Clinic Laboratory: Coagulation
Useful For
Measuring heparin concentration in patients treated with unfrationated heparin preparations
Methodology
Chromogenic Substrate Assay
Specimen Requirements
Specimen Collection and Handling:
- Draw blood in a light blue-top (3.2% sodium citrate) tube(s).
- Immediately after draw, gently invert tube(s) at least 6 times to mix well.
- Spin down, remove plasma, spin plasma again, and place 1.5 mL of citrate platelet-poor plasma in plastic vial immediately after specimen collection
- Double-centrifuged specimens are critical for accurate results as platelet contamination may cause spurious results.
- Freeze specimen immediately at -20° C.
- Glass vial is not acceptable.
Specimen Transport:
- Send specimen frozen.
- DO NOT refrigerate
Storage/Stability
| Specimen Type | Temperature | Time |
| Plasma | Ambient | 8 hours |
| Frozen (preferred) | 4 weeks |
Reject Due To
- Clotted
- Incorrect collection tube
- Gross hemolysis
- Incorrect fill volume (too full or not enough)
- Specimen received refrigerated
Reference Values
Therapeutic concentration: 0.3 - 0.7 U/mL
Critical Value: >0.8 U/mL
Day(s) Test Set Up
Daily
Test Classification and CPT Coding
85520 - Heparin assay
LOINC Code Information
| Reporting Name | LOINC Code |
| Heparin Assay | 3274-8 |