Table 1 Desiccant in RDTs

1. Presence of desiccant in device packaging

Desiccant protects the RDT from humidity before the device packaging is opened[20]

2. Humidity indicator

  2.1. Presence of humidity indicator (self-indicating, partial-indicating, non-indicating (Figure 1)

Desiccant with a colour indicator of humidity is preferred[1]

  2.2. Composition of humidity indicator (based on colour appearance)

Cobalt dichloride should be avoided[24, 25, 27]

3. Material of desiccant sachet:

  3.1. Permeable

Sachet should be vapor permeable to allow humidity uptake

  3.2. Transparent

  Colour of beads easily visible with no additional light source needed, additional light source needed, sachet not transparent precluding inspection of colour change

Sachet should be transparent to allow easy colour check of the humidity indicator

4. Warning message on sachet:

  4.1. Not to eat the content of the sachet

The desiccant may be harmful if swallowed, so it should be kept away from children[20]

5. Information available in instructions for use:

  5.1. To check the colour of the silica gel after opening the device packaging

Silica gel colour should be checked upon opening of device packaging[19, 21–23]

  5.2. How to interpret the colour change of the silica gel

Interpretation of colour indication should be mentioned in IFU or on sachet

  5.3. What to do when the silica gel is saturated

The RDT should be discarded and a new RDT should be used[21–23]

  5.4. To discard the sachet after colour has been checked

Once the packet is opened, the sachet should be discarded[20]

  5.5. Information on properties, safety hazards, remedies and safe disposal of the desiccants should be provided by the manufacturer

It is the responsibility of the manufacturer to provide accurate information on this[1]