Latex fixation test

The latex agglutination method is used clinically in the identification and typing of many important microorganisms. These tests are based on and utilize the patient's antigen-antibody immune response. (This response occurs when the body detects a pathogen and forms an antibody specific to an identified antigen (a protein configuration) present on the surface of the pathogen.)

Agglutination tests, specific to a variety of pathogens, can be designed and manufactured for clinicians by coating latex beads with pathogen-specific antigens. In performing a test, laboratory clinicians will mix normal saline serial dilutions (important because of the prozone effect) of a patient's CSF, serum or urine with the coated latex particles and observe for agglutination. Agglutination/clumping of the beads in any of the dilutions is considered a positive result, confirming that the patient has produced the pathogen-specific antibody. [Instances of cross-reactivity can lead to confusing results.]

Agglutination techniques are used to detect antibodies produced in response to the rubella virus or to the rheumatoid factor. There is an excellent LA test for cryptococcus.^[1] Agglutination techniques are also used in definitive diagnosis of Group A streptococcus.

See also

• Visceral_leishmaniasis#Diagnosis

External links

• Latex fixation test at the US National Library of Medicine Medical Subject Headings (MeSH)
• Singer JM, Edberg SC, Selinger M, Amram M (1979). "Quality control of the latex-fixation test". Am. J. Clin. Pathol. 72 (4): 591–6. PMID 495562. 
• Description of the test

References