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Test Code PCACTB or LAB489 Protein C Activity, Plasma

Important Note

Please contact the laboratory if the patient's hematocrit is over 55%, as a special tube must be provided for the blood draw.

Specimen Requirements

Specimen Type:

Whole Blood

Container Type:

Blue top: 2.7 mL or 1.8 mL

Optimal Collection Volume:
  • 2.7 mL in solid blue top tube or 1.8 mL in clear blue top tube.  The correct fill volume is indicated by the etched line on the tube.
  • Click here to view the specimen collection guide for blue top (citrate) tubes.

Collection Instructions:
  1. Gently invert 5 to 10 times to mix blood.
  2. If collected through a blood collection set (butterfly), a discard tube must first be drawn to eliminate dead space from tubing.
  3. Specimens are good for 4 hours from the time of draw when stored at room temperature

Specimen Transport Temperature:
  • Room temperature up to 4 hours. If testing is delayed, separate plasma and freeze (see outpatient collection instructions below).
  • Specimens cannot be refrigerated

Processing Instructions:
  1. Centrifuge sample within 4 hours of collection. Platelet-poor plasma must be obtained per laboratory procedure.
  2. If testing will be delayed >4 hours from collection, aliquot plasma into a separate vial and freeze immediately.

Outpatient collections

  1. Spin down the sample, remove plasma, and spin plasma again to obtain platelet-poor plasma.
  2. Separate the platelet-poor plasma into a screw-top vial.
  3. Freeze plasma immediately.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Specimen Stability

Specimen Type

Temperature

Time

Whole blood

Room Temperature

4 hours

Platelet Poor Plasma

Room Temperature

4 hours

Platelet Poor Plasma

Frozen at -20 C

2 weeks

Specimen Rejection Criteria

  • Tube underfilled
  • Refrigerated specimen
  • Clotted specimen

Useful For

Initial test for evaluating patients suspected of having congenital protein C deficiency, including those with a personal or family history of thrombotic events. 

 

Detecting and confirming congenital Type I and Type II protein C deficiencies, detecting and confirming congenital homozygous protein C deficiency, and identifying decreased functional protein C of acquired origin (e.g., due to oral anticoagulant effect, vitamin K deficiency, liver disease, intravascular coagulation, and fibrinolysis/disseminated intravascular coagulation).

 

Because coagulation testing and its interpretation are complex, Bronson Laboratory suggests ordering the Thrombophilia Cascade (LAB2692). 

Methodology

Performed using the Hemosil Protein C kit on the ACL TOP 500

Reference Ranges

70-140%

Day(s) Performed

Monday/Wednesday/Friday - Day shift only

Expected TAT

Same day to 3 days

Performing Laboratory

Bronson Laboratory, Coagulation - Kalamazoo

Sample Retention Time

1 month

CPT Code

85303

LOINC Code

5964-2