[Reliability and agreement of two smear reading scales for classification and monitoring of multidrug therapy in leprosy patients].
BACKGROUND
After the clinical diagnosis of leprosy, classification methods are necessary to define a treatment and prognosis of patients consistent with bacterial load. Bacteria are detected in skin smear, and bacterial load typically is established by the internationally used Ridley's logarithmic scale, However, in Colombia an alternative semiquantitative scale is used.


OBJECTIVE
The interobserver reproducibility was established for the Ridley and Colombia scales, and the level of correlation-matching was identified between the bacillary indices obtained in order to assess the degree of interchangeability.


METHODS
Standardization was attained by a reading of the smears by 2 readers with subsequent, blinded evaluation of inter-observer agreement. Each reader quantified the bacterial load of for each sample (n=325) using the Colombian and the Ridley scales. The degree of interobserver agreement was assessed with weighted kappa coefficient. The level of correlation and agreement between the measurements of the bacillary index was established with coefficient of Lin.


RESULTS
The interobserver weighted kappa coefficient was 0.83 for the Colombia scale and 0.85 for the Ridley scale. The Lin coefficient was 0.96 for the correlation-matching of bacillary indexes.


CONCLUSIONS
Interobserver agreement obtained for both scales was excellent as the correlation-matching bacillary indices determined with both methods. With the cut-off points yielded a good level of agreement, ensuring interchangeability between the scales defining the high or low bacterial load.
Centro Dermatológico Federico Lleras Acosta, E.S.E, Bogotá, D.C, Colombia.
Claudia Lucía
CL
Colorado
Guillermo
G
Sánchez
Martha Inírida
MI
Guerrero
Clara Inés
CI
León
D058491:Bacterial Load / Q000379:methods*; D001706:Biopsy / Q000379:methods / Q000592:standards*; D002965:Classification; D016903:Drug Monitoring / Q000379:methods*; D004359:Drug Therapy, Combination; D004431:Ear, External / Q000382:microbiology; D006801:Humans; D007917:Leprostatic Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D007918:Leprosy / Q000188:drug therapy / Q000382:microbiology*; D009166:Mycobacterium leprae / Q000187:drug effects / Q000302:isolation & purification*; D009297:Nasal Mucosa / Q000382:microbiology*; D015588:Observer Variation; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016037:Single-Blind Method; D012867:Skin / Q000382:microbiology*; D013194:Staining and Labeling
D007917:Leprostatic Agents