What are other Names for this Test? (Equivalent Terms)
- Activated Protein C Resistance Blood Levels Test
- APCR Blood Test
What is the Activated Protein C Resistance Blood Test? (Background Information)
- Protein C is an anti-coagulant and anti-inflammatory enzyme. It requires protein S, a coenzyme, and vitamin K to function. Protein C is similar to aspirin in its “blood-thinning” effects
- Protein C is made in the liver, while protein S is made in the inner lining of blood vessels. Both protein C and protein S circulate in the bloodstream
- Protein C activates during clotting process to keep blood clotting under control. Clotting is essential to minimizing blood loss. However, like every other process in the body, clotting is tightly regulated
- Activated protein C (APC) exerts its anticoagulant effects by removing clotting factors, including factor V, and stimulating plasmin, a protein that degrades blood clots (a process called fibrinolysis)
- APC deactivates clotting factors by recognizing and attacking specific sites on their structures. If APC could not recognize these sites, it would be unable to deactivate the factors. This would make blood that is oversensitive to clotting.
- Activated protein C resistance (APCR) is a disorder in which clotting factors are resistant to deactivation by APC
- 90% of APCR cases are caused by a genetic mutation in the region of DNA that gives instructions for factor V, a key clotting factor. The factor V that is produced possesses an alteration in the key recognition site for APC. Thus, activated protein C is unable to recognize and deactivate the defective factor V, which causes APCR
- The Activated Protein C Resistance Blood Test measures the prolongation time of blood clotting after APC has been added to a sample of blood. It is used to diagnose Activated protein C resistance
What are the Clinical Indications for performing the Activated Protein C Resistance Blood Test?
Following are the clinical indications for performing the Activated Protein C Resistance Blood Test:
- Following up to blood tests that identify a blood clotting sensitivity
- Presence of an internal blood clot
- Leg pain
- Chest pain
- Rapid pulse
How is the Specimen Collected for the Activated Protein C Resistance Blood Test?
Following is the specimen collection process for Activated Protein C Resistance Blood Test:
Sample required: Blood
Process of obtaining blood sample in adults:
- A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
- The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
- The needle cap is removed and is held in line with the vein, pulling the skin tight
- With a small and quick thrust, the vein is penetrated using the needle
- The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
- The wrap band is removed, gauze is placed on the collection site, and the needle is removed
- The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
- The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the Activated Protein C Resistance Blood Test Result?
- A high Activated Protein C Resistance Blood Test value may indicate activated protein C resistance (or APCR) disorder
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
•Pregnancy may interfere with the results of the Activated Protein C Resistance Blood Test
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.
Please visit our Laboratory Procedures Center for more physician-approved health information: