Evaluation of protein C and protein S levels during oral anticoagulant therapy.
A number of workers have examined protein C in relation to other vitamin K dependent factors during warfarin therapy and successfully identified protein C deficient patients by ratio calculation. However, protein S deficiency has not been addressed in this manner. This study compares protein C and protein S by functional and antigenic determination with procoagulant factors of similar half life (Factors VII and II) in an attempt to identify protein C and protein S deficient patients whilst on oral anticoagulant therapy. Procoagulant and anticoagulant factors were compared by linear regression in a population of normal blood donors and patients on stabilized warfarin therapy to obtain expected values for protein C and protein S dependent upon FVII and FII levels, respectively. Observed over expected values for protein C and protein S were calculated for individual patients and normal ranges derived. Comparison of similarly calculated observed over expected protein C and protein S ratios with these normal ranges successfully identified known protein C and protein S deficient patients who were taking warfarin at time of testing.
Department of Haematology, General Infirmary at Leeds, UK.
A E
AE
O'Brien
G M
GM
Tate
C
C
Shiach
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use*; D000941:Antigens / Q000032:analysis; D005167:Factor VII / Q000032:analysis; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D011486:Protein C / Q000276:immunology / Q000378:metabolism*; D020151:Protein C Deficiency / Q000097:blood / Q000188:drug therapy; D017293:Protein S / Q000276:immunology / Q000378:metabolism*; D018455:Protein S Deficiency / Q000097:blood / Q000188:drug therapy; D011516:Prothrombin / Q000032:analysis; D012016:Reference Values; D013927:Thrombosis / Q000188:drug therapy; D014859:Warfarin / Q000008:administration & dosage / Q000627:therapeutic use*
D000925:Anticoagulants; D000941:Antigens; D011486:Protein C; D017293:Protein S; D014859:Warfarin; D005167:Factor VII; D011516:Prothrombin