Related Experiment Videos
Anticoagulant response to activated protein C: method validation and assay comparison
T Calkins1, J Greengard, J H Griffin
1Scripps Reference Laboratory, San Diego, CA 92121, USA.
Insights
Activated protein C (APC) resistance, a common issue in thrombophilia, is often due to factor V mutations. This study validated an assay for APC resistance, finding differences in response based on sex and age.
Area of Science:
- Biochemistry
- Hematology
- Clinical Diagnostics
Background:
- Activated protein C (APC) resistance affects 20-60% of thrombophilic patients.
- The common cause is the factor V Arg506Gln mutation, confirmed by DNA sequencing.
- Understanding APC resistance is crucial for diagnosing thrombotic disorders.
Purpose of the Study:
- To validate an in-house assay for detecting APC resistance.
- To compare the in-house assay with a commercial kit.
- To investigate demographic differences in APC response.
Main Methods:
- Validated an in-house assay for APC resistance at Scripps Reference Laboratory (SRL).
- Studied 80 healthy subjects (40 males, 40 females, aged 21-60).
- Compared SRL assay results with a commercial kit (Chromogenix, Coatest).
Main Results:
- Significant differences in APC response were observed between adult males and females.
- APC response increased with age in normal individuals.
- The SRL assay showed a greater difference in normal ranges between sexes compared to the commercial kit.
- 44% of thrombophilic patients were identified as APC-resistant.
- Individuals with the factor V Arg506Gln mutation showed low APC response in both assays.
Conclusions:
- The validated SRL assay effectively identifies APC resistance.
- Demographic factors like sex and age influence APC response.
- APC resistance testing aids in diagnosing thrombosis and assessing familial risk.
Abstract:
Poor anticoagulant response to activated protein C (APC), present in 20-60% of thrombophilic patients, is most often caused by abnormal factor Va due to the mutation of Arg506 to Gln, and DNA sequencing confirms this finding. At Scripps Reference Laboratory (SRL), we have validated an in-house assay to detect APC resistance. A study of 80 normal subjects (40 males and 40 females, 21-60 years old) showed that adult males and females have statistically significant differences in their anticoagulant response to APC. Furthermore, APC response is increased in older individuals. APC responses of the same 80 normal samples determined using the SRL assay were compared to a commercial kit (Chromogenix, Coatest). Although both procedures are similar, the SRL assay gave a greater difference between male and female normal ranges. Eight of 18 (44%) thrombophilic patients were identified as APC-resistant. Samples from individuals having the factor V Arg506Gln mutation yielded low responses to APC in both assays. Determination of APC resistance assists physicians in determining the cause of thrombotic disorders and may eventually help in predicting the risk of familial thrombosis.