The Use of Plasma in the Kline Test for Syphilis.

Abstract

Among the several successful precipitation methods for the diagnosis of syphilis recently developed the Kline microscopic slide test has been found to be one of the most satisfactory. Though more sensitive than other tests it is nevertheless highly specific.

Considerable time is usually expended in the collection and separation of the patient's serum, even though the performance of the test itself may be accomplished within 5 minutes. At the suggestion of Dr. Bronfenbrenner, the use of plasma, rather than serum, has been tried as a means of shortening the time that must elapse between the taking of a blood sample and the completion of a test. Since plasma can be collected much more rapidly and easily than serum, its use offers the possibility of making a presumptive diagnosis in a few moments after taking of the blood, while the patient waits in the clinic or office.

Plasma specimens were secured by taking blood into tubes containing sodium citrate (final concentration 0.1%). A separate portion of each blood sample was allowed to clot for control tests on the serum. The citrated blood tubes were centrifugalized at once and the plasma collected.

Experiments showed that for the proper performance of the test inactivation of the plasma was necessary. Heating at 56°C. for only 10 minutes was found to be sufficient.

After inactivation the plasma must be recentrifugalized very briefly to remove a heavy amorphous precipitate. The supernatant clear plasma may then be used immediately for the test.

The reaction of the plasma as compared with that of the serum of 212 individuals has been tested by the Kline method. There was an agreement in the reading of the serum and plasma reaction in 76.9% of cases.