Cool Chain Requirement for SCT

A cold chain is a system of transporting and storing TB specimens at optimum temperature while being transported from the peripheral health institutions to the diagnostic labs to reduce the growth of contaminating endogenous respiratory organisms.

Cold chain requirements for transportation of TB diagnostic specimens are (Figure 1):

• A thick thermocol box (one-time use box), which has a thickness of about 2.5 cm. Outer dimensions of the box - Length: 18.5 cm, Breadth: 13 cm, Height: 12 cm. Inner dimensions of the box - Length: 14.5 cm, Breadth: 8 cm, Height: 10 cm.
• Two gel packs to maintain a temperature between 12-20°C for up to approximately 48 hours in tightly packed thermocol boxes (average outside temperature 35°C). Gel packs to be conditioned in the deep freezer (temperature between -20 to -15°C) for a minimum of 48-72 hours before use.

Figure 1: Technical specifications of transport box for sputum specimen transportation in cold chain

Specimen Transport  Steps - Cold Chain (Figure 2)

1. Place the gel pack into the thermocol box. 
2. Place the sample tubes (in zip-lock pouches) on the frozen gel packs.
3. Keep the pouch containing the Test Request form on top before placing another gel pack on top. 
4. Close the lid of the box and wrap tightly with brown duct tape to maintain the cold chain.

Figure 2: Steps for specimen transportation in cold chain

Resources

• Guidelines for Programmatic Management of Drug Resistant Tuberculosis in India, March 2021.

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