Al-i-quot: An amount that is an exact divisor of the whole quantity of a substance (Collins Dictionary of Medicine, R. Young, 2005).

Why aliquot QC material?

Aliquoting QC material can extend the open vial stability of a lyophilised control, according to manufacturer recommendations. By splitting your QC material into a number of tubes and freezing these you can extend the working stability of the control, ultimately reducing wastage and the amount of money spent on unnecessary additional controls.

Example

A laboratory purchases a lyophilised QC with a volume of 3ml once reconstituted the control is stable for 7 days at 2-8^oC. However, the laboratory only uses 1ml of this control per week, meaning that 2ml could potentially be wasted. The manufacturer states that the control can be frozen after reconstitution, extending the working stability from 7 days at 2-8^oC to 30 days at -20 ^oC to -80^oC. The following outlines the process for aliquoting reconstituted material and extending the control’s working stability.

Aliquoting reconstituted material

1. Reconstitute the QC material according to the manufacturer’s instructions.
2. Using a micropipette aliquot the required volume (generally a minimum of 0.5ml should be used) of reconstituted material into a tube.
3. Repeat step 2 until all the reconstituted material has been aliquoted.
4. Label each tube with the date the material was reconstituted to avoid the use of expired material.
5. Store each aliquot at -20^oC in a frost free freezer. Be sure to check the kit insert for frozen stability claims.
6. Remove and thaw each aliquot as and when required making sure to use all material within the frozen stability period.
7. Once thawed do not refreeze, dispose of any leftover QC material.

Conclusion

Aliquoting reconstituted material is an ideal way of extending the control’s open vial stability. This will ensure that your laboratory minimises the amount of QC material wasted and saves money by eliminating the need to purchase additional controls. Please note that not all lyophilised controls can be frozen like this. To ensure the controls you are selecting are suitable for aliquoting check the product’s kit insert or contact your supplier.

What can Randox Quality Control offer?

We have a number of lyophilised controls which can be prepared and stored in this way across our extensive product portfolio. To find out more visit www.randoxqc.com or contact us via acusera@randox.com to arrange a visit from one of our QC Consultants.