The reaction of A cells with anti-A, B cells with anti-B, O cells with Ulex europaeus anti-H is reduced by heat (56 degrees C) treatment. This is demonstrated using an automated haemagglutination technique with which minor differences in reactions can be detected.

Sucrose density gradient ultracentrifugation can be used to detect specific 19S antibodies of the IgM class in the sera of patients recently infected with influenza A virus, provided steps are taken to remove non-specific inhibitors of haemagglutination. The usefulness of the procedure for the diagnosis of influenza requires further evaluation.

Synopsis A short history of the laboratory diagnosis of pregnancy is followed by an evaulation of four immunological methods of pregnancy diagnosis. The immunological methods based upon haemagglutination-inhibition and slide latex agglutination, gave a.lOO% accuracy. It is concluded that these techniques are suitable for the diagnosis of pregnancy after the 35th day following the last menstrual...

Optimal conditions for carrying out the indirect haemagglutination test with sheep erythrocytes were studied using the microtitre system. The age of the erythrocytes, concentration of reagents, time and temperature of tanning, sensitization, and incubation are described with reference to replication of titres. Sera from patients with amoebic colitis were used to evaluate the test conditions.

During 1982-83, 1161 sera were examined for the presence of haemagglutinating antibodies against Toxoplasma gondii. The Indirect Haemagglutination Test (IHAT) was positive in 416 (35.8%). Fourteen patients were judged to be suffering from acute acquired toxoplasmosis (active disease). In addition, 11 patients were also found to have glandular fever.

An automatic method, utilizing the AutoAnalyzer, for titration of influenza virus haemagglutination inhibitors is described. The titres obtained compare favourably with those obtained by densitometric methods. So far, the technique has not proved superior to the densitometric methods in either speed of operation or in reproducibility but various developments are suggested to effect this.

Fowlpox (FP) is a serious disease in chickens caused by Fowlpox virus (FPV). One method currently used to control FPV is vaccination followed by confirmation that antibody titres are protective using the indirect haemagglutination assay (IHA). The direct haemagglutination inhibition (HI) assay is not done because most FPV strains do not agglutinate chicken red blood cells (RBCs). A novel FPV st...

Human 0 erythrocytes, treated with 1% formalin and subsequently exposed simultaneously to hydatid protein antigen and 0.1% chromic chloride, acquire the property of agglutinating on a slide when brought in coontact with specific antiserum. This constitutes the basis of the slide haemagglutination test, an easy, quick, sensitive, and specific procedure, usefull in the diagnosis of hydatid disease.

Two haemagglutination tests using preserved turkey erythrocytes are described for the detection of thyroglobulin and microsomal antibodies, respectively. Comparative studies with the more traditional sheep cell techniques show good correlation of titres when testing sera from patients with autoimmune thyroid disorders.

A simple haemagglutination procedure is described which measures antibodies that react with capsular antigens of Haemophilus influenzae. Abnormally high antibody titres of appropriate type-specificity are common in the blood of human subjects who are known to have carried capsulate strains of H. influenzae. It is not yet clear whether all such antibodies are due to such carriage.