Performance of variations of carbolfuchsin staining of sputum smears for AFB under field conditions.
METHODS
A field project in Bangladesh.


OBJECTIVE
To compare the effectiveness of commonly used carbolfuchsin staining variations.


METHODS
Routine hot Ziehl-Neelsen (ZN) 1% basic fuchsin staining for 15 min in 75 field clinics. Blind reading of duplicate smears stained by ZN 1% vs. 0.3% basic fuchsin applied for 5 min, or by ZN 1% 5 min vs. Kinyoun cold staining. Rechecking of discordant series.


RESULTS
For comparable numbers of false positives, sensitivity was significantly lower with Kinyoun than with ZN 1% 5 min (85.6% vs. 93.0%, P < 0.001). Sensitivity with ZN 1% 5 min was not significantly higher than with 0.3% 5 min staining (89.9% vs. 86.5%). Routine examination using 1% 15 min ZN identified more positives than any of the study techniques.


CONCLUSIONS
Kinyoun cold staining sensitivity was unsatisfactory in field clinics. The sensitivity of the WHO/IUATLD recommended 0.3% fuchsin for 5 min was not significantly different from the original 1% ZN for 5 min, but 1% 15 min hot staining might be superior. A reduced fuchsin concentration together with a short staining time may leave too narrow a margin for error. TB programmes using hot ZN with a concentrated stain or longer staining time should not be urged to change.
Van Deun
A
A
Mycobacteriology Unit, Institute of Tropical Medicine, Antwerpen, Belgium. avdeun@itg.be
Hamid Salim
A
A
Aung
K J M
KJ
Hossain
Md A
MA
Chambugonj
N
N
Hye
Md A
MA
Kawria
A
A
Declercq
E
E
D001459:Bangladesh / Q000453:epidemiology; D016009:Chi-Square Distribution; D004396:Coloring Agents; D006801:Humans; D008853:Microscopy; D012394:Rosaniline Dyes; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D013194:Staining and Labeling / Q000379:methods*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology
D004396:Coloring Agents; D012394:Rosaniline Dyes; C006898:carbol-fuchsin solution