Reconstituting Lyophilised Controls
What is Lyophilisation?
Lyophilisation or ‘freeze drying’ is the process by which water is removed from a product after it is frozen and placed under a vacuum, allowing the ice to change directly from solid to vapor without passing through a liquid phase. The process consists of three separate processes:
- Primary Drying (Sublimation)
- Secondary Drying (Desorption)
There are many benefits to using a lyophilised control including; improved product shelf-life and enhanced stability of volatile analytes. For example, many lyophilised controls have a shelf life of up to four years from the date of manufacture resulting in a reduction of costly new lot validation studies. Furthermore, lyophilised controls can be aliquoted and refrozen to extend the working stability of the product.
Reconstituting Lyophilised QC Material
The process of reconstitution involves adding a specified volume of distilled water to lyophilised QC material. The water should completely dissolve the lyophilised contents, giving a liquid solution, which is ready for analysis.
Reconstitution is a straightforward process, but requires a high level of precision. Small errors can have serious implications to the reconstituted material:
- If too much water is pipetted during reconstitution, the material will be heavily diluted and results will be lower than expected
- If too little water is pipetted during reconstitution, the material will not be sufficiently diluted, and results will be higher than expected
- If the correct volume of water is pipetted, but a small amount of water gets stuck in the pipette tip due to poor pipetting technique, results will be higher than expected
If a lyophilised control has been reconstituted incorrectly the contents of the vial will be wasted. It is therefore vitally important that controls are reconstituted with care.
Materials and Methods Required
The list of requirements for an accurate and consistent reconstitution technique is not extensive, but each requirement is vital. Labs should have:
- Calibrated volumetric pipettes
- Sterile, appropriately sized pipette tips
- Distilled water, or other reconstitution fluid as specified
- Technician with good pipetting technique
- Lyophilised QC stored according to manufacturer’s specifications
How to Reconstitute Lyophilised QC Material
Each different lyophilised control may require slightly different preparation, always refer to the instructions for use before reconstituting control material. The below guide provides a general overview of the reconstitution process, using the Randox Human Assayed Chemistry Premium Plus control (HN1530) as an example
- Place the vial of lyophilised QC on a flat surface, carefully remove the lid and the rubber stopper making sure not to spill any material
- Using a calibrated pipette and sterilised pipette tip, add exactly 5ml of distilled water directly into the QC vial, ensuring no water is left in the pipette tip, or on the rim/side of the vial
- Place the rubber stopper and lid firmly back onto the QC vial, and leave to stand for 30 minutes
- After 30 minutes, gently invert the QC vial 10-15 times to ensure the contents is completely dissolved, making sure to avoid the formation of foam. It is important that you DO NOT SHAKE the vial. Alternatively place the vial on a roller for 30 minutes to ensure the contents is thoroughly mixed
- Once satisfied all material has been completely dissolved, proceed to use the QC product in accordance with the ‘Control’ section of the individual analyser application
- Once finished, refrigerate any unused material. It is good practice to label the vial with the date of reconstitution to prevent the use of material outside of the recommended stability period
- Prior to reusing lyophilised material, mix the contents thoroughly by gentle inversion, as highlighted in Step 4
It is important to remember that there may be slightly different reconstitution requirements for different QC material. For this reason, it is vital that the instructions provided on the QC Kit Inserts are closely followed.
Reconstituting lyophilised QC can be time-consuming. Therefore, Randox Acusera offer convenient 5ml distilled water serum diluent to assist laboratories with reconstitution of lyophilised controls. These user-friendly pour over vials streamline the reconstitution process and eliminate the risk of pipetting errors.
If you have any further questions regarding lyophilised controls or would like to contact us, please do so by emailing us at firstname.lastname@example.org or use the contact us button provided.
An important consideration when choosing your Quality Control material that is often overlooked is the shelf life of the control. With every new lot of control extensive validation studies must be performed. Regulatory bodies such as CLIA require new lot numbers to be evaluated before routine use in the laboratory. For example, CLIA has instructed that any new control lot to be run alongside patient samples will need to be verified alongside the old lot of control. The process is designed to give laboratory professionals confidence in the new material and ensure it is fit for purpose before implementing it in the lab.
As part of the validation process laboratories are required to assay both the old and new lots side by side. The current lot is then used to help verify if the new lot will be acceptable to run within the lab. Such validation studies can be very costly for a lab as well as being extremely time consuming – with some studies taking up to a month to complete! By choosing a control with a longer shelf life laboratories can aim to use the same lot of control for a longer time period. Ultimately this means fewer lot changes and minimal inconvenience for the lab. With a shelf life of 2 years for liquid controls and up to 4 years for lyophilised, coupled with unrivalled stability claims, employing Randox Quality Control in your laboratory will ensure that expensive lot changes will be a thing of the past. Our comprehensive control offering is guaranteed to increase efficiency and reduce costs in any laboratory without compromising on quality.
Contact us today to find out more information on our Acusera range of Quality Controls.
Results of our Liquid vs Lyophilised Poll
Having conducted a recent poll on our Social Media platforms (Facebook, LinkedIn & Twitter) asking our customers what format they preferred their quality control material in – liquid or lyophilised – we saw a large preference for liquid controls.
What does this poll result really tell us?
That most people prefer Liquid controls? Yes.
Lyophilised controls are not as popular amongst our social following? Yes.
However, it also tells us that even though most people chose a liquid format there was still almost a quarter of people who prefer to use lyophilised controls. Liquid and lyophilised controls both have their advantages and disadvantages, this blog is designed to help you decide which is the best fit for your lab.
Firstly, it is important to note that there are two distinct types of liquid control available on the market;Liquid ready-to-use and Liquid for ease-of-use, better known as Liquid Frozen. Both types of liquid controls reduce the potential for reconstitution errors and prevent contamination from poor quality water.
Liquid frozen controls must be thawed in a refrigerator before use, making them a little less convenient than the liquid ready-to-use alternative. They require no reconstitution so associated errors are removed. Due to the frozen nature of these controls, they are often shipped on dry ice to prevent thawing in transit, as such transportation costs can be significant.
Liquid ready-to-use controls are arguably the most favoured of the three formats and it is easy to understand why. The controls are simple to use, they require no preparation and there is no need to thaw before use.– With zero preparation required, these controls can be removed from the packaging and used right away! What’s more, they can be conveniently stored at 2-8oC minimising expensive shipping costs.
Another major benefit of using a liquid ready-to-use control is the fact that they are ideal for POCT (Point of Care Testing). The ability to use these controls on the spot is extremely beneficial to POC providers.
Lastly, the choice of 22% of respondents – lyophilised. This is freeze dried material which requires the laboratory professional to reconstitute the sample using sterilised water and mixing before use. Although this format is not as easy to use as either liquid control it does come with benefits. The enhanced stability of this control sees a shelf life of almost double the two years that is normal with a liquid control, however, the potential for reconstitution errors and the fact it is not as simple to use lead to the majority of people opting for a more convenient liquid control.
Randox Quality Control Range
With Randox QC there are a vast array of controls available in liquid ready-to-use and liquid frozen formats. Areas we have liquid frozen formats available in, include; Clinical Chemistry and Immunoassay.
Liquid ready-to-use controls can be found in the following; Liquid Cardiac, Blood Gas, Liquid Urine, Urinalysis, Specific Protein, Ammonia Ethanol, Haematology, Liquid HbA1c and Liquid Tumour Markers.
To register an interest in any of our controls simply contact us at acusera@Randox.com and let us know how we can help and support you or alternatively click here – where you will be redirected to our contact page.