Protein-C (protein C) is a protein (protein) from the blood clotting system that is produced in the liver. It inhibits factors V and VIII.Protein-C is vitamin K-dependent.
A cofactor of protein-C is protein-S.
Protein-C deficiency results in an increased risk of thrombosis.
The procedure
Material needed
- Citrate plasma
Preparation of the patient
- Not necessary
Disruptive factors
- Completely fill the monovette, there should be no coagulation
- The analysis should be done within a few hours (otherwise freeze).
- Deviation of the hematocrit from its normal value.
- Hemolysis / lipemia
Normal value – protein C activity
| Normal value in % | |
| 1st day of life (mature/immature) | 12-44 |
| 5th day of life (mature/immature) | 11-53 |
| 1st month of life (mature/immature) | 15-59 |
| 3rd month of life (mature/immature) | 23-67 |
| 6th month of life | 31-83 |
| > 1. year of life/adults | 70-140 |
Normal value – protein C concentration
| Standard value in mg/l | |
| Adults | 2-6 |
- Determination only useful in case of decreased activity
Indications
- Suspicion of increased thrombotic tendency (thrombophilia screening).
Interpretation
Interpretation of increased values
- Taking oral contraceptives (birth control pills).
- False elevated levels in the presence of lupus anticoagulant, high heparin concentration.
- Pregnancy
Interpretation of lowered values
- Genetic protein C deficiency – homozygous/heterozygous protein C deficiency.
- Elevated factor VIII levels (falsely low).
- Factor consumption due to:
- ARDS (acute respiratory distress syndrome).
- Disseminated intravascular coagulation; disseminated intravascular coagulation (DIC syndrome, for short; consumption coagulopathy).
- Sepsis (“blood poisoning”).
- Trauma (injuries)
- Cirrhosis of the liver – connective tissue remodeling of the liver, which leads to functional limitations.
- Renal insufficiency (kidney weakness): affected are dialysis patients.
- Vitamin K deficiency (Marcumar therapy)
Further notes
- Decreased protein C concentrations are associated with an increased risk of thrombosis or thromboembolism.
- During marcoumar therapy, protein C determination is not useful because protein C synthesis (formation) is vitamin K-dependent.
