The sputum gram stain.
D005840:Gentian Violet; D006801:Humans; D010619:Phenazines; D012141:Respiratory Tract Infections / Q000382:microbiology*; D013183:Sputum / Q000382:microbiology*
C035863:Gram's stain; D010619:Phenazines; D005840:Gentian Violet