Factors Affecting the Passive Hemagglutination Titration: Dilution Loops, Titration Trays, Vibration, Diluents1

Abstract

Serial dilution with Takatsy loops resulted in exaggerated passive hemagglutination titers with most of the anti-bovine serum albumin sera tested. It appears that certain types of agglutinins adhere to the loop surface and are released only gradually. This adherence, or carry-over effect, was prevented by presoaking loops in gelatin or gelatin-rabbit serum-albumin solutions. Hemolysins did not adhere to loops. In general, hemagglutination reactions performed on plastic trays gave higher titers than those performed in glass test tubes. The quality of the hemagglutination pattern was dependent to a great extent on the type of plastic tray used. As much as a 100-fold difference in titers was obtained depending on the composition of the antiserum diluent. The increase in vibration, in terms of linear displacement (approximately twofold), resulted in an eightfold decrease in titers. Although the passive hemagglutination (HA) test is one of the most simple and widely used immunological assays, it lacks reproducibility. I This study was performed in part while one of the authors (L.R.D.) was associated with the National Cancer Institute,

Pharmacological properties of MDL 19,301: A novel, nonsteroidal, anti‐inflammatory agent

“…Rabbit antiserum to bovine serum albumin (BSA, Sigma Chcmical Co., St. Louis, MO) was produced in rabbits using the procedure described by Hirata et al [1969]. Reaginic antiserum to ovalbumin (OA, Sigma) was produced in Brown Norway rats using a published method [Baldo et al, 19801.…”

Use of Stable, Sensitized Cells in Indirect Micro Hemagglutination Test for Amebiasis

“…Preparation and sensitization of the red blood cells is time consuming and day-today variation is not unusual. It has been shown that several factors, such as the type of plastic tray, antiserum diluent, microtitration loops, antigenic variation, and the use of various batches of red blood cells, influence the IHA titer in some systems (6). The present study was undertaken to try to overcome some of these problems.…”

Statistical Evaluation of Diluents and Automatic Diluting and Pipetting Machines in Influenza Serology

“…In recent years, automation of these microtechniques has enabled laboratories to increase their volume of testing. Few investigators, however, have reported on the standardization and comparative reproducibility of the HA and HI tests utilizing these newer methods (1)(2)(3). Because of this, and because standardized procedures are necessary for the correct interpretation of serological test results, we investigated the reproducibility of the HA and HI tests for influenza by comparing the standard tube test with the microtechniques performed by hand (7) and by use of semiautomatic equipment (6,10).…”