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Test Code PROT-CF Protein C Activity (Functional)

Specimen Requirements

Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
*Platelet Poor Plasma 3.2% 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 Frozen 6 months

Rejection Criteria

Clotted or Hemolyzed
Contaminated with IV or Hickman Line fluids
Specimens that thaw storage or transport

Test Information

Do not order if the patient has received Coumadin for the past two weeks. If patient is on a stable dose of Coumadin (2 weeks), see Protein C Antigen, On Coumadin test (PROT-CM).


See Clinical Practice Guidelines - Hypercoagulability for more information

Reference Range Information

Performing Location Reference Range
Marshfield 70-140 % 

Marshfield Labs Performing Department

Marshfield Labs Hematology

Performing Information

Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield Monday and Thursday Less than 2 hours Chromogenic assay /IL ACL TOP 550

CPT Codes

CPT Modifier
(if needed)		 Quantity Description Comments
85303        

Outreach CPT Codes

CPT Modifier
(if needed)		 Quantity Description Comments
85303        

Ordering Applications

Ordering Application Description
Centricity Protein C Activity
Cerner Protein C Activity
COM Protein C Activity

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