Blood, 1960, Vol. 15, No. 3, pp. 404-412.
© 1960 American Society of Hematology, Inc.
The Preparation of Plasma Thromboplastin Antecedent
(PTA) and its Assay with Purified Clotting Components
HAROLD GALLICK 1,
L. A. HYNDMAN 1, and
K. B. MCCALL 1
1 Division of Laboratories, Michigan Department of Health, Lansing, Mich.
By replacing the three crude reagents commonly used in thromboplastin
generation tests—washed platelets, barium sulfate- or alumina-adsorbed
plasma, and serum—with purified clotting factors, many variables and
uncertainties were eliminated. It was demonstrated that plasma thromboplastin antecedent (PTA) was required for the generation of thromboplastic
activity.
A method was developed for the preparation of purified PTA from fraction
IV-1 of human plasma. Its identity was established by its ability to correct,
in vitro, the defect in the plasma of a PTA-deficient patient. Thus, further
evidence in support of the belief that PTA is a discrete component, essential
for blood coagulation, was obtained. More specifically, it was found to be
essential in the generation of thromboplastic activity in plasma.
A test system for thromboplastin generation was described which was
used to assay PTA in vitro and which did not require the use of PTA-deficient plasma or serum. Omission of any one of the components of this
system resulted in a marked loss of thromboplastic activity; restoration of
activity was proportional to the amount of the component that was added.
Thus, with this system of purified components, it was possible to assay any
one of them without the use of, or requirement for, plasma or serum
specimens from patients with specific coagulation deficiencies.
Submitted on May 14, 1958
Accepted on July 31, 1959
