Detection of protein C or protein S deficiency in patients on warfarin therapy--a study of nine patients

Area of Science:

• Hematology
• Clinical Medicine
• Genetics

Background:

• Protein C and protein S deficiencies are inherited conditions increasing thrombotic risk.
• Diagnosing these deficiencies can be challenging, especially in patients on anticoagulant therapy like warfarin.

Purpose of the Study:

• To investigate methods for diagnosing protein C and protein S deficiencies in patients presenting with thrombotic events.
• To evaluate the utility of specific coagulation factor ratios in identifying protein C deficiency in warfarinized patients.

Main Methods:

• Review of 9 cases of young to middle-aged patients with thrombotic events and suspected protein C or S deficiency.
• Family studies to identify affected relatives with low protein C or S levels.
• Serial measurement of protein C, factor II, and factor X at various International Normalization Ratio (INR) levels.

Main Results:

• Clinical features were consistent with known thrombotic tendencies in protein C/S deficiency.
• A correlation was observed between warfarin anticoagulation (INR) and the suppression of vitamin K-dependent factors.
• Distinguishable differences in protein C levels and ratios (protein C: factor II, protein C: factor X) were found in warfarinized protein C deficient patients compared to non-deficient controls.
• A similar diagnostic pattern was not identified for protein S deficiency, potentially due to assay limitations.

Conclusions:

• Specific coagulation factor ratios can aid in diagnosing protein C deficiency even in patients receiving warfarin therapy.
• This diagnostic approach may help identify individuals at risk for thrombotic events associated with protein C deficiency.
• Further investigation into diagnostic methods for protein S deficiency in warfarinized patients is warranted.