Calculation of the ELISA’ s cut-off based on the change-point analysis method for detection of Trypanosoma cruzi infection in Bolivian dogs in the absence of controls
Mem. Inst. Oswaldo Cruz
;
111(8): 501-504, Aug. 2016. tab
Article
in English
| LILACS
| ID: lil-789002
ABSTRACT
In ELISAs, sera of individuals infected by Trypanosoma cruzi show absorbance values above a cut-off value. The cut-off is generally computed by means of formulas that need absorbance readings of negative (and sometimes positive) controls, which are included in the titer plates amongst the unknown samples. When no controls are available, other techniques should be employed such as change-point analysis. The method was applied to Bolivian dog sera processed by ELISA to diagnose T. cruzi infection. In each titer plate, the change-point analysis estimated a step point which correctly discriminated among known positive and known negative sera, unlike some of the six usual cut-off formulas tested. To analyse the ELISAs results, the change-point method was as good as the usual cut-off formula of the form “mean + 3 standard deviation of negative controls”. Change-point analysis is therefore an efficient alternative method to analyse ELISA absorbance values when no controls are available.
Full text:
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Index:
LILACS (Americas)
Main subject:
Trypanosoma cruzi
/
Enzyme-Linked Immunosorbent Assay
/
Antibodies, Protozoan
/
Chagas Disease
/
Dog Diseases
Type of study:
Diagnostic study
Limits:
Animals
Country/Region as subject:
South America
/
Bolivia
Language:
English
Journal:
Mem. Inst. Oswaldo Cruz
Journal subject:
Tropical Medicine
/
Parasitology
Year:
2016
Type:
Article
/
Project document
Affiliation country:
Bolivia
Institution/Affiliation country:
Institut de Recherche pour le Développement/BO
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