Preparation of TB Lab Disinfectants

Disinfectants used in lab settings include:

1% Sodium Hypochlorite

• Broad spectrum antimicrobial action
• Used to disinfect surfaces
• Used to disinfect infectious material and disposal of used Truenat consumables (reagent bottles, cartridges, tips, chips) 
• Hazardous and corrosive, to be used with care
• Is highly alkaline so can corrode metal
• Waste soaked in Sodium Hypochlorite should not be discarded by autoclaving. 

70% Alcohol

• Bactericidal action
• Used for surface decontamination only
• Highly inflammable; keep away from fire
• Used to disinfect biosafety cabinets, laboratory benches and surface of instruments.

5% Phenol

• Used for decontaminating Cartridge-based Nucleic Acid Amplification Testing (CBNAAT) equipment and single-use items like CBNAAT cartridges prior to disposal
• Highly irritating to the skin, eyes and mucous membranes.

Preparation of these disinfectants is described below.

Preparation of 1% Sodium Hypochlorite

• Use commercially available 4% sodium hypochlorite solution.
• Dilute with distilled water to prepare required amount of 1% sodium hypochlorite
  • E.g.: To prepare 100 ml of 1% sodium hypochlorite: 75 ml distilled water plus 25 ml 4% sodium hypochlorite solution.
• Sodium hypochlorite solutions (domestic bleach) contain 50 g/l available chlorine, and should therefore be diluted to 1:50 or 1:10 in water to obtain the final concentrations of 1 g/l or 5 g/l when used as a general-purpose disinfectant for TB laboratories.
• To be prepared fresh.

Preparation of 70% Alcohol

• Use commercially available absolute alcohol.
• Dilute with distilled water to prepare the required amount of 70% alcohol
  • E.g.: To prepare 100 ml of 70% alcohol: 70 ml absolute alcohol plus 30 ml distilled water.

Preparation of 5% Phenol

• Melt 5 g of phenol by heating it.
• Dissolve in 100 ml distilled water.

Video : Preparation of TB Lab Disinfectants

Resources

• Tuberculosis Laboratory Biosafety Manual