Serological tests

Learn how serology testing is performed, how to prepare, and how to interpret results together with a clinician.

Meningococcus: antibodies and laboratory diagnostics

Detection of antibodies to meningococcus is used to diagnose meningococcal infection in bacterial and serous meningitis, as well as urethritis.

Haemophilus influenzae: antibodies and immune assessment

Agglutination and precipitation tests are used for serological diagnosis of diseases caused by influenza bacilli. Determination of antibodies to Haemophilus influenzae in serum is a retrospective method for diagnosing the disease, as serum must be tested during the first week of illness and 10-14 days later.

Pneumococcus: serum antibodies and clinical significance

Serological diagnosis of pneumococcal infection is aimed at detecting the titer of anticapsular antibodies in the patient's serum. An increase in the antibody titer over 7-10 days when testing paired sera is considered diagnostic.

Staphylococcus: antibodies and when they are informative

Serological methods for diagnosing purulent-septic diseases include the direct hemagglutination test and ELISA. An increase in antibody titer after 7-10 days when testing paired sera is considered diagnostic.

Antibodies to streptococci: groups A, B, C, D, F, G

Antibodies to group A streptococcal polysaccharide (group-specific polysaccharide - anti-A-CHO) appear in the first week of infection, their titer rapidly increases, reaching a peak by the 3rd-4th week of the disease.

Parvovirus B19: antibodies in erythema infectiosum

IgM antibodies to parvovirus B19 are detected in 90% of patients 4-7 days after the onset of clinical symptoms. Antibody levels gradually increase, peaking at 4-5 weeks, and then decline. IgM antibodies to parvovirus B19 can persist in the blood for 4-6 months after the disease.

Coxsackie: antibodies to viruses and when they are prescribed

The complete serum count (CS), hemagglutination assay (HIA), and neutralization assay (NSAID) are used to detect antibodies to Coxsackieviruses in blood serum. Paired sera are tested during the acute phase of infection and 2-3 weeks after the onset of illness.

Respiratory syncytial virus: antibodies and diagnosis

To detect antibodies to the respiratory syncytial virus, a CSF test or ELISA is used. CSF testing is performed at the onset of the disease and 5-7 days later. A four-fold increase in antibody titer when testing paired sera is considered diagnostically significant, but this testing method is less sensitive in children under 4 months of age.

Adenoviruses: antibodies and laboratory confirmation

To detect antibodies to adenoviruses, a complete serum count (CSC) or an ELISA (enzyme immunoassay) are used. With CSC, testing is performed at the onset of the disease and 5-7 days later. A fourfold increase in antibody titer when testing paired sera is considered diagnostically significant.

Parainfluenza: antibodies to types 1, 2, 3, 4

Compared to the CSF test, the ELISA method (which detects IgM and IgG antibodies) is more sensitive (according to various authors, from 49% to 94%). However, as with the CSF test, its diagnostic use requires comparing antibody titers in serum samples obtained from patients at the onset and end of the disease.

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