Serological tests

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

Tularemia: antibodies and laboratory diagnostics

ELISA is a more sensitive and specific method for diagnosing tularemia, detecting IgA, IgM, and IgG antibodies. Detection of IgM antibodies or a four-fold increase in IgG titer confirms acute infection or reinfection in the presence of the corresponding clinical picture.

Lyme Disease: Borrelia Antibodies and Testing Stages

In Lyme disease, specific IgM antibodies typically appear in the blood 2-4 weeks after the onset of erythema migrans, with peak antibody levels occurring between 6-8 weeks of illness. In stage 1, IgM antibodies are detected in 40-60% of patients.

Pseudotuberculosis: antibodies to the pathogen and diagnostics

Determining the antibody titer to the pseudotuberculosis pathogen in serum is a retrospective method for diagnosing pseudotuberculosis. Paired sera from the patient are tested. To detect specific antibodies, blood is collected at the onset of the disease and 7-10 days after the initial test.

Yersiniosis: antibodies and laboratory confirmation

Determination of antibodies to the causative agent of yersiniosis is used to diagnose yersiniosis, including bacterial arthritis, Reiter's disease, Behcet's syndrome, and infectious arthropathies.

Whooping cough: antibodies to Bordetella pertussis and diagnostics

In recent years, test systems have been developed that detect IgA, IgM, and IgG antibodies to Bordetella pertussis antigens in serum using ELISA. IgM antibodies appear in the blood three weeks after the onset of the disease and can therefore be used to confirm the etiological diagnosis. The dynamics of IgA antibody titers to Bordetella pertussis toxin are largely similar to those of IgM.

Diphtheria: Toxin antibodies and protection assessment

Serological methods for diagnosing diphtheria include the indirect hemagglutination assay and ELISA. The titer of antibodies to diphtheria toxin is determined at the onset of the disease (days 1-3) and 7-10 days later. A titer increase of at least fourfold is considered diagnostic.

Tuberculosis: antibodies to the pathogen and limitations of the method

Detection of antibodies to the tuberculosis pathogen in serum is a new and highly promising method for serologically diagnosing tuberculosis. The currently used bacteriological method for isolating Mycobacterium tuberculosis is time-consuming (4 to 8 weeks) and is highly effective primarily for pulmonary tuberculosis.

Salmonellosis: antibodies and laboratory confirmation

Currently, the most widely used methods for detecting antibodies to salmonella (to the O-antigen) are RPGA and ELISA; they are more sensitive than the Widal reaction and give positive results from the 5th day of the disease (the Widal reaction - on the 7-8th day).

Brucellosis: antibodies to the pathogen and diagnostics

Brucellosis is caused by Brucella, a small, non-motile, gram-negative bacterium. When diagnosing brucellosis, clinical and epidemiological data must be confirmed by laboratory testing.

Neisseria meningitidis antigen in cerebrospinal fluid: a rapid test

Of great importance for the early diagnosis of meningococcal infection is the study of cerebrospinal fluid in patients with meningeal symptoms to detect Neisseria meningitis antigens.

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