To xml of sputum, add 2xml of 4% NaOH

Tighten cap of container and shake to digest

Let stand for 15 minutes at  room temperature with occasional shaking

Centrifuge at 3 000 x g for  15 minutes

Pour off supernatant

Add 15ml sterile saline or distilled water and resuspend sediment

Centrifuge at 3  000 x g for 15 minutes

Decant supernatant and inoculate onto culture medium immediately