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PubMed1982

Sensitivity and specificity of two microtitre complement fixation tests for the diagnosis of Brucella ovis infection in rams.

An investigation was made into microtitre complement fixation test (CFT) procedures suitable for the serological diagnosis of naturally occurring Brucella ovis infection in rams. A procedure similar to the Australian standard procedure for bovine brucellosis was unsatisfactory when applied to sheep. Modification of the procedure by use of an initial serum and anticomplementary control dilution of 1:8 and increasing complement fixation time to 60 minutes at 37 degrees C, greatly improved the efficiency of the test. A sensitivity of 100% was recorded for 59 serums from known infected rams and a specificity of 99.9% for 1593 serums from rams known or believed to be free of infection. Some aspects of applying CF tests to sheep serums are discussed.

Animals↗
PubMed1987

Antibody response in patients infected with Campylobacter jejuni/coli assayed with a complement fixation test and a DIGELISA method.

Two methods for the detection of antibodies against Campylobacter jejuni/coli, a complement fixation test (CFT) and a DIG-ELISA method, were tested against a panel of single sera from 36 coproculture positive patients. Twenty-five were positive in CFT compared to 31 in the other system. Twenty-three out of 25 CFT positive sera were positive in the ELISA method. Seven sera were positive only for IgA antibodies thus negative in the CFT. CFT may be useful for the detection of IgG/IgM antibodies against C. jejuni/coli. However, serum IgA may be a valuable marker for infections with C. jejuni/coli. Methods such as DIG-ELISA may identify such cases.

Antibodies, Bacterial↗
PubMed1975

A specific complement-fixation test for human hepatitis a employing CR326 virus antigen. Diagnosis and epidemiology.

A specific diagnostic complement-fixation test for hepatitis A antibody in human serum was described employing livers of marmosets infected with CR326 strain human hepatitis A virus. Persons with hepatitis A, but not hepatitis B, developed hepatitis A CF antibody shortly after the onset of illness and this persisted thereafter. Good agreement was noted in the development of CF and neutralizing antibodies in hepatitis A cases. Hepatitis A was shown to occur in a person with hepatitis B antigenemia and hepatitis B occurred in persons with hepatitis A antibody. Most persons with hepatitis A who were tested, but none of those with hepatitis B, developed increased anticomplementary activity in their sera at the time of onset of illness. At least one patient with hepatitis A developed antibody against normal liver that persisted. The possible inplications of this in relation to pathogenesis and to non-specific diagnostic tests in hepatitis were discussed. A limited epidemiologic study of a family outbreak of hepatitis in Costa Rica and of a group of young adults in our epidemic country acquire their infections at an early age and are immune thereafter; persons in areas of relatively low incidence may proceed into adulthood without experience with hepatitis A. The CF test should provide an excellent tool for diagnosis and for epidemiologic investigation of hepatitis A and should be of considerable value to detect hepatitis A virus in attempts to propagate the virus in cell culture.

Adolescent↗
PubMed1976

A comparison between the haemagglutination inhibition and complement fixation tests for Newcastle disease.

The value of the complement fixation (CF) test as a means of assessing the immune response of fowls to Newcastle disease virus was examined using several strains of virus. A close degree of correlation was found between the CF test and the simpler haemagglutination-inhibition (HI) test. Like the HI test, the CF test only gave an indication of the immune status and was not a direct measurement of immunity.

Animals↗
PubMed2004

Evaluation of an automated complement-fixation test (Seramat) for diagnosis of acute respiratory infections caused by viruses and atypical bacteria.

The complement-fixation test (CFT) permits low-cost screening of serum samples for different agents within a single assay, and is a useful tool for the serological diagnosis of acute respiratory infections. This study evaluated the automated Seramat CFT system with 160 paired serum samples taken from 80 patients with acute respiratory infection in comparison with in-house CFTs against a panel of agents, including influenza A and B, adenovirus, respiratory syncitial virus, cytomegalovirus, Mycoplasma pneumoniae, Coxiella burnetti and Chlamydia spp., and in comparison with indirect immunofluorescence (IIF) against Legionella pneumophila. Overall, the Seramat system identified 75 (88.2%) of the 85 seroconversions recognised by in-house CFTs or IIF. In comparison to the in-house CFTs, the correlation was 89.2% (66/74). For L. pneumophila, the Seramat system detected nine (81.8%) of the 11 cases diagnosed by IIF. The Seramat system also identified eight additional seroconversions that were not detected by the in-house assays; none of these seroconversions was detected by the in-house assay on retesting. The Seramat system represents a significant technical improvement that may enable many clinical laboratories to use the CFT as a routine diagnostic tool.

Acute Disease↗
PubMed1977

Complement fixation test of Nebraska calf diarrhea virus with calf serum.

A complement fixation (CF) test for neonatal calf diarrhea has been developed with Nebraska calf diarrhea virus (NCDV) as antigen. The CF antigenicity of NCDV appeared in BK cell cultures for the first time 3 days after inoculation. Usually, the unconcentrated BK cell culture fluid infected with NCDV possessed poor CF antigenicity. The fluid concentrated by ultracentrifugation and ultrafiltration and with polyethylene glycol 6000 revealed a high-titered CF antigenicity to antiserum against NCDV. The antigen was not sensitive to lipid solvents, but was relatively resistant to heating. It was recognized that the concentrated fluid of cell culture infected with NCDV was available as antigen in the CF test for the serological demonstration of infection with a calf reovirus-like agent. The wide prevalence of diarrhea among Japanese calves with the calf reovirus-like agent was revealed from the results of CF and neutralization tests of NCDV.

Animals↗
PubMed1980

A complement-fixation test for enzootic pneumonia of pigs using a complement dilution method.

Complement-fixing antibody to Mycoplasma hyopneumoniae in the serums of pigs experimentally infected with enzootic pneumonia was demonstrated by comparing the haemolytic titre of guinea-pig complement titrated in the presence of heated test serum, M. hyopneumoniae antigen and unheated normal pig serum with the titre obtained when the antigen was omitted. The haemolytic titres against sensitised sheep erythrocytes were determined after a fixation period of 16 to 18 hours at 5 degrees C. When serums, collected at intervals of 3 to 7 days, from 43 pigs exposed to pigs experimentally infected with enzootic pneumonia were tested, 4.6 or more complement units were first fixed 14 to 44 (mean 23.4) days after contact began. Serums collected subsequently fixed from 4.6 to more than 31 complement units. This positive reaction usually persisted until the pigs were killed 4 to 35 weeks after contact began. Thirty-three had gross enzootic pneumonia lesions and 9 had lung lesions detected microscopically. Serum antibody was not detected in 73 weaned pigs aged 7 weeks in a pneumonia-free herd but serums from 9 of 15 unweaned piglets aged 9 to 14 days in the same herd, fixed between 3 and 7 complement units.

Animals↗
PubMed1975

A rapid slide flocculation test for the diagnosis of American trypanosomiasis using Trypanosoma cruzi fragments preserved by lyophilization. Comparison with hemagglutination, immunofluorescence, and complement fixation tests.

A slide flocculation test for Chagas' disease is described, which uses a lyophilized, stable antigen obtained by formalin and ultrasonic treatment of culture forms of Trypanosoma cruzi. The test was compared with other tests for the serodiagnosis of American trypanosomiasis and showed a high sensitivity, positive results being obtained in every case of acute or chronic Chagas' disease. In sera from blood donors and from normal individuals with negative T. cruzi antigen complement fixation tests a specificity of 96% was found. False positive flocculation tests were seen, especially in cases of South American blastomycosis and in a few cases of acute toxoplasmosis. Since it is easy and quick to perform, the slide flocculation test can be recommended as a screening procedure, especially for blood banks.

Bacterial Infections↗