presented at the American Society of
Microbiology 106th National Meeting, May 26, 2006
Poster C-324:
Evaluation of Four Commercially Available
Auramine O Stain Sets
Schlacks, M.1, Coppernoll, S. 2, DeBoo,A. 1, Schmidt, A. 1,
Bartnicki, L. 1, Schreckenberger, P. 1 and Lipton, S. 2 , 1Loyola
Medical Center, Maywood, IL; 2Scientific Device Laboratory,
Des Plaines, IL
Background: With a dramatic increase of incidence of Mycobacterial
disease, it is more important than ever to find rapid methods
for identification of the organism. The current fluorescent
techniques to identify acid fast organisms in smears take from
20-30 minutes to perform. The purpose of this study was to compare
the qualitative intensity of fluorescence and quantitative time
of staining of three commercially available Auramine O stain
sets with that of a recently introduced rapid method which takes
2 minutes to perform. The four stains used were TB Auramine
O Kit (Remel), TB Fluorescent Stain Kit Auramine M (BD), Auramine
O Stain Kit (MCC) and the new Rapid Modified Auramine O (Scientific
Device Laboratory). Methods: Four sets of smears were prepared
from 185 patient specimens. Each was stained using the four
fluorescent techniques outlined in the technical insert provided
by each company. The first three commonly used stain sets use
a three-step procedure utilizing stain, decolorizer and permanganate.
The new Rapid Modified Auramine O procedure differed by utilizing
a two-step procedure in which the decolorizer and quenching
agent were combined together. The entire smear area of 20mm
was scanned by an experienced technologist under low power for
any fluorescence. If fluorescence was seen, the objective was
switched to oil for organism confirmation. Relative intensity
of fluorescence was measured on a scale of 1-4 on all positive
smears. Results: A total of 13 (7%) patient smears were positive
using all four stains. The staining intensity was equal for
all techniques used. One (0.5%) specimen was positive with MCC
stain and SDL Stain only. There was one additional smear that
was weakly positive only with the SDL stain. In both these latter
cases the clinical diagnosis corresponded with the positive
smears. When the cost was compared from the list price of each
of the stain sets, the Rapid Modified Auramine O (SDL) was less
expensive than the others, especially when considering the technologist
staining time. The fluorescent intensity on positive specimens
was equivalent. Conclusion: All stain sets tested gave equivalent
results. The Rapid Modified Auramine O was less expensive and
could be performed in 1/5 of the time required for conventional
Auramine staining.