Quick Review Cards for Medical Laboratory Science

Acid-Fast Stains Clinical Microbiology Review 209

STAIN PRIMARY STAIN DECOLORIZER COUNTERSTAIN APPEARANCE OF AFB OTHER

Ziehl-Neelsen

Kinyoun

Fluorochrome

AFB = acid fast bacilli. OI = oil immersion.

Requires heat. Examine at

least 300 OI fields. Wipe

lens after pos smears to

avoid cross-contamination

& false pos.

Cold stain. Examine at least

300 OI fields. Wipe lens

after pos smears to avoid

cross-contamination &

false pos.

More sensitive than carbol-

fuchsin. Faster to read.

Can examine at 250×.

Read immediately or store

at 2°C–8°C in dark to avoid

fading. Examine at least

300 fields. Pos should be

confirmed with carbol-

fuchsin stain. Rapid grow-

ers might not stain.

Methylene blue

Methylene blue

Potassium per-

manganate or

acridine orange

Carbolfuchsin

Carbolfuchsin

Auramine- rhodamine

Acid alcohol

Acid alcohol

Acid alcohol

Red, slightly curved,

beaded rods (2–8 μm).

Blue background.

Red, slightly curved,

beaded rods (2–8 μm).

Blue background.

Yellow-orange rods

against dark background.