A Micro-Method for the Determination of the Combined Activity of Factor II and VII (Prothrombin and Proconvertin)

Summary

A Micro-method for the determination of the combined activity of factors II and VII (prothrombin-proconvertin) based on the techniques of Owren and Koller et al. using capillary blood plasma, is being described. 0.18 ml of the free flowing blood from either the ear lobe or the finger tip is sucked into a micro-pipette previously containing 0.02 ml of anticoagulant. 0.05 ml of the centrifuged plasma is used to make a 1 : 10 dilution with buffered saline for the test. The clotting times in seconds are converted to percentages from the standard dilution curve plotted on double log. paper. Results obtained on over 300 capillary blood samples from in-patients receiving long term anticoagulant therapy were compared with those done by both Owren’s technique and the described micro-method on venous blood plasmas. These results were closely identical with each other.

^*) Present address: Gerinnungsphysiologisches Labor (Prof. F. Koller) der Med. Klinik, Kantonsspital, Zürich, Switzerland.

• References

• 1 Koller F, Loeliger A, Duckert F, Hu-Wang H. Über einen neuen Gerinnungsfaktor (Faktor VII) und seine klinische Bedeutung. Dtsch. Med. Wschr. April, Nr 1952; 17: 528-533.
• 2 Owren P. A, Aas K. The Control of Dicumarol Therapy and The Quantitativc Determination of Prothrombin and Proconvertin. Scand. J. Clin. Lab. Invest 3: 201 1951;
• 3 Toohey M. Comparison of Quick’s, Owren’s and Ware’s techniques for the control of Anticoagulant Therapy. J. Clin. Path 1958; 11: 1-56.