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HelpTest Code APC-R Activated Protein C Resistance Assay
Useful For
Activated Protein C (APC) is a major regulator in the blood/coagulation system. APC plays an important role in inhibiting blood clotting by degrading the phospholipid-bound Va and VIIIa.
This assay measures anticoagulant response in plasma added APC. The expected result of a normal plasma would be a prolongation of the activated partial thromboplastin time (aPTT) due to the inactivation of factors VIIIa and Va.
The addition of APC to the plasma of some patients with a history of unexplained multiple thrombotic events did not result in a normal response as measured by the aPTT.
Special Collection Instructions
Properly filled 9:1 ratio (blood to anticoagulant); gentle inversion, minimum 6 times, at time of collection
Collection Method
Venous Draw; properly filled 9:1 ratio (blood to anticoagulant)
Minimum Volume
0.5 ml of plasma from a properly filled 1.8 mL or 2.7 mL NaCitrate (light blue) tube
Container
Light Blue Sodium Citrate
Preferred Specimen
2.7mL Lt. Blue (3.2% NaCitrate)
Acceptable Specimens
1.8 mL Lt. Blue (3.2% NaCitrate) tube
Reference or Target Ranges
>2.28
Reportable Units
Ratio
Critical Value
Not defined for this assay
Reasons for Rejection
| Hemolysis Threshold | N/A |
| Icterus Threshold | N/A |
| Lipemia Threshold | N/A |
| Interfering Subtances/Other | Short draws, over draws, clotted, improperly labeled, hemolyzed, lipemic or icteric samples, samples > 4 hours from collection |
Specimen Stability
| Ambient | Plasma – 4 hours |
| Refrigerated (4°C to 8°C) | N/A |
| Frozen(-70°C to -20°C) | 2 weeks@ -20°C; 1 year @ -70°C |
Performance Information
| Days and Time Performed | Batched weekly Monday-Friday |
| Expected Turn Around Time | Batched Monday – Friday |
| Stat Availability | No |
| Performing Bench | Coagulation |
| Instrument: | Werfen ACL TOPS |
| Methodology/Method Description | APTT Based Assay |
Additional Information/Important Notes
After being spun down twice, separate plasma into 2 aliquot tubes and transport to University Hospital Laboratory frozen on dry ice.
CPT Codes
85307