Processing sputum specimen for Tb

Dennis Gaunt dgaunt at uhl.uiowa.edu
Tue Dec 16 14:54:57 EST 1997

yoram keness (rakeness at internet-zahav.net) wrote:
: Dear Colleagues!
: I have come accross a practice of processing sputum specimen for
: Mycobacteria which I would like to share with you:
: In preparing the Kinyoun stain, the technician was instructed to do two
: things:
: first to open the container with the sputum specimen and try to "fish" an
: especially                                  big clump of puss and place it
: on a glass slide. Decontamination\ NALC treatment of                       
:     remaining sputum followed, and after centrifugation another ca. 0.06 ml
: of the pellet                                  were pipetted on top of the
: first (in the meantime dried out) spot.
: As soon as this one was dry, Kinoun staining followed.
: The argument has it, that doing it this way increases the sensitivity of
: the Kinyoun stain.
: Acid fast bacilli that might have been damaged through the decontamination
: process will be 
: "compensated" for by the ones that remained intact in the pretreated
: specimen.                                          Has this ever been
: proven for the NALC procedure?
: This procedure (the "fishing") is exteremly messy and I wonder whether it
: does the job.
: Can anyone comment on the effectiveness of this procedure? is it worthwile
: the mess and
: danger we are exposing the staff in sending them out "fishing"?
: Thanx
: Y. Keness

In my opinion, this is a waste of time and, possibly, risky.  In
an appropriate centrifuge, the afb will be concentrated in the pellet
anyway, so why do the direct portion from the specimen?  

| Dennis D. Gaunt                   | Internet: dgaunt at uhl.uiowa.edu | 
| The University of Iowa            |    Voice: (319) 335-4500       |
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