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| Test Description |
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Test Name
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Activated Protein C Resistance |
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Synonym
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APCR, APC Resistance, APC-R |
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Description
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Protein C, in the presence of thrombin bound to thrombomodulin, is cleaved to an enzymatically active form, Activated Protein C (APC). APC is an important natural anticoagulant which functions by inactivating Factors Va and VIIa. Recently, people have been described with an abnormal Factor V molecule (Factor V Leiden) which is resistant to inactivation by APC. APCR is a functional assay for FV Leiden and it is almost 100% sensitive in identifying APCR due to FV Leiden. This causes thrombosis in the patient. |
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Methodology
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Clotting |
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Performed
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Wednesday |
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Turnaround Time
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1-7 days |
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Specimen Requirements
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3 mL platelet-poor citrated plasma (light blue 3.2% sodium citrate tube). Freeze plasma within 4 hours of collection in 1 mL aliquots.
Transport frozen.
Minimum volume 2 mL.
Coagulation Drawing Instructions:
- When drawing coagulation tests, always draw a “pilot” tube (7-10 mL plain red top tube, completely filled). This removes tissue fluid contamination, discard pilot tube.
- Draw blood in a light blue (3.2% sodium citrate) top tube. Fill tubes as far as vacuum will fill and mix gently. Ratio of anticoagulant and blood must be maintained. Avoid slow flowing draws and traumatic venipunctures.
- Spin vacutainer – remove plasma avoiding platelet/buffy layer – spin plasma again – remove top portion of plasma and place 1 mL of PLATELET-POOR PLASMA in plastic tube. (Glass tube unacceptable)
- Double-centrifugation is critical for accurate results as platelet contamination may cause erroneous results.
- Plasma must be frozen within 4 hours of collection.
- CRITICAL WARNING: Specimen must remain frozen until testing. Submit separate aliquots when multiple tests are ordered on same patient specimen.
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Rejection Criteria
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Plasma hemolyzed, thawed or contaminated with heparin. |
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CPT Code(s)
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85307 |
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Reference Range
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See interpretive report. |
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Contact Information
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Hemostasis Lab: 214-645-5067
Customer Service: 214-645-7057, Toll Free 877-887-8136 |
Last Modified: March 11, 2008 |
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