utum

Collect 5 to 10 mL in a sterile container from an early

morning specimen of deep productive cough. For induced

specimen use sterile saline. Have patients rinse mouth

with water to minimize specimen contamination with

food particles, mouthwash, or oral drugs.

Urine

As organisms accumulate in the bladder overnight, first

morning void provides best yield. Collect midstream clean

catch urine, first morning catheterization/suprapubic taps

in sterile containers.

856 Concise Book of Medical Laboratory Technology: Methods and Interpretations

Specimen Preparation

Proper decontamination and concentration of specimen

containing normal microbial flora are crucial to

detection of Mycobacterium tuberculosis. Specimen

obtained from sterile sites such as CSF, peritoneal or

pleural fluids do not need decontamination. However,

since most specimens for AFB smear and culture are

from respiratory tract and mucous traps AFB and

protects other organisms from decontamination and

concentration, decontamination and liquefaction is a

must. Most satisfactory for this purpose is a combination

of N-acetyl-cysteine (mucolytic agent) and 2% NaOH

(decontaminant). Petroffs method of decontamination

can also be used.