Hemagglutination-inhibition tests

There is no routine test for the diagnosis of trivial or cutaneous arachnidism. The use of a passive hemagglutination inhibition test has been used successfully to identify venom from Brown Recluse spider bites in animal studies. This test has not yet been used for diagnostic purposes in human trials and is not routinely available to clinicians. 

Barrett SM, Romine-Jenkins M, and Campbell JP (1989) Passive hemagglutination inhibition test for diagnosis of Brown Recluse spider bite envenomation. Annals of Emergency Medicine 18 441. 

The first immunological assay for TSH was based on the cross-reaction of human and bovine TSH in a hemagglutination inhibition test however, this method was too insensitive for chnical purposes. Immunoassay measurement of serum TSH concentration did not become a routine test until the purified pituitary hormone became available for immuniz,ation and iodination. 

Precision. Figures for the index of precision (A) using such techniques do not yet appear to have been calculated. According to Stockell and Hartree (S25), the precision of hemagglutination-inhibition tests is reasonably satisfactory in skilled hands, the fiducial limits of... 

As in hemagglutination-inhibition tests, a predetermined amount of antibody to the hormone in question is incubated with a series of dilutions of unknown or standard solutions of the gonadotropin. After a period of preincubation ranging from 0 to 3 days, labeled hormone is added to each tube, and the mixture is reincubated to equilibration. 

For the reasons discussed previously (Section 7.3.5.I.), radioimmunoassays are unlikely to be any more useful than hemagglutination-inhibition tests for work in which the identity of the hormone in question is important. There is no reason to expect that indices of discrimination between radioimmunoassays and bioassays will be any better than those between hemagglutination-inhibition tests and bioassays. However, radioimmunoassays for FSH and LH are extremely sensitive, and can probably provide a satisfactory indication of pituitary function in health and disease. For this reason, it is virtually certain that such procedures will be employed on an ever increasing scale in the management of patients. 

Hemagglutination inhibition test Serologic test used to diagnose measles, influenza, and other viral diseases, based on the abih-ty of antibodies to viruses to prevent viral hemagglutination. 

Elliott and Emmons (1971) described a passive indirect hemagglutination test, and a corresponding inhibition test for measuring residual chymosin in cheese. They also produced high titer antisera for E. parasitica protease and M. pusillus protease, and suggested that these enzymes could also by quantitatively detected in cheese. 

Rubella Virus. Antibody to rubella virus is currently detected in most laboratories by the hemagglutination inhibition (HI) test. Since there are relatively few people in the normal population who do not have antibody to this virus, 20 sera which were negative by HI were tested by RIA, in addition to the 100 sera from source A. A comparison between the HI and RIA showed almost complete agreement in distinguishing positive from negative sera (99% see Table III). A comparison of the titers obtained by these two tests gave a correlation coefficient of 0.30 and p<0.05 that this coefficient differs from zero by chance alone. One reason for the poorer correlation between the titers of these two tests is that they may be de-... 

A Comparison of Rubella Virus Hemagglutination Inhibition (HI) and Magnetic Radioimmunoassay (RIA) Tests... 

In indirect or passive hemagglutination, the erythrocytes are used as a particulate carrier of foreign antigen (and in some tests of antibodies) this technique has wide applications. Other materials available in the form of fine particles, such as bentonite and latex, also have been used as antigen carriers, but they are more difficult to coat, standardize, and store. In a related variation of tliis technique, known as hemagglutination inhibition, the ability of antigens, haptens, or other substances to specifically inhibit hemagglutination of sensitized (coated) cells by antibody is determined. 

It is clear that the degree of immunological cross-reaction between various antigens varies with the type of assay used. Nakai and Parlow raised an antiserum to highly purified LH and, using a microcomplement fixation test, were able to show that HCG did not cross-react with this antiserum. However, the same antiserum did react in both the hemagglutination-inhibition and radioimmunoassay systems (Nl). Schuurs et al. 

Practicability. Both hemagglutination-inhibition and latex inhibition tests are easy to perform and are inexpensive. In addition, the results of the tests can be read in a few hours. As mentioned previously, their main disadvantage is the need to use large quantities of purified hormones in order to coat the red cells. Stockell Hartree (S25) has shown that these assays are extremely useful in order to monitor hormone extraction procedures, but in the absence of a supply of purified hormones their sphere of applicability to clinical problems is limited. When crude hormones and nonspecific antisera are used the quantitative significance of assays based on hemagglutination-inhibition reactions is doubtful. 

The basis of the radioimmunoassay is similar to that for hemagglutination inhibition, in that an antigen (or in radioimmunoassay it may be a hapten) is labeled, and used to compete, quantitatively, with unlabeled hormone (standard or test) at the antibody surface. 

RAST (radioallergosorbent test) or enzyme assay (IgE, IgG) Histamine liberation from granulocytes Basophil degranulation test Passive hemagglutination Lymphocyte transformation test Macrophage inhibition test Rosette test... 

From the results of plaque-neutralization (L-cells) and hemagglutination-inhibition (human erythrocytes) tests. 

The mammalian reoviruses are divided into three serotypes (1, 2, and 3) on the basis of hemagglutination inhibition and antibody neutralization tests (Rosen, 1960). Reovirions contain a segmented, double-stranded RNA (dsRNA) genome surrounded by two concentric icosahedral protein shells (Gomatos et ai, 1962). There is an internal core containing the genome and a closely applied inner capsid surrounded by an outer capsid shell (Smith et ai, 1969 Fig. 1). 

Finally, the clusters were tested as inhibitors of hemagglutination of pig and rabbit erythrocytes by type-1 piliated UTI89 clinical isolate E. coli. The inhibition titer (IT), that is, the lowest concentration of the inhibitor at which no agglutination occurs, showed tetramer 51 to be the best inhibitor of hemagglutination, with an IT of about 3 fiM, or a factor of 6000 as compared to its affinity, and corresponding to 1000-fold better inhibition than that induced by D-mannose. Overall, tetravalent cluster 51 was the best noncovalent cross-linker of Con A and the best ligand known to E. coli K12 FimH. 

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