The pre-analytical phase of laboratory testing includes collection, handling, transportation, storage, and preparation of samples. Even when the highest level of care is taken to ensure that all aspects of the pre-analytical phase are suitable and correct, errors can occur, exhibiting the need for clear and efficient quality control processes.

As part of our Acusera quality control range, Randox has developed the Serum Indices quality control to aid in the detection of the common pre-analytical error’s haemolysis, icterus and lipemia, collectively known as HIL. HIL interference can have disastrous effects on the quantification of many analytes, and it is therefore vital to determine levels of interference to improve laboratory efficiency and reduce the frequency of erroneous results.

The graph below shows the wavelengths at which each of these interferents may affect assays and the table below describes these forms of interference:

Classical determination of HIL interference took the form of a visual assessment. A sample was examined for tell-tale signs of one or more of these types of interference. However, these methods are subject to operator interpretation and lack harmonisation and uniformity across the industry.  These signs are detailed in the table and illustrated in the graphic below:

Modern clinical chemistry analysers have onboard HIL detection capabilities which offer objective, semi-qualitative or qualitative analysis of these forms of interference in a more precise and consistent manner. Automation of HIL detection improves laboratory throughput along with test turnaround times and enhances the reportability of the results.

Errors at any stage of the analytical process will result in retesting of the sample. Errors in the pre-analytical phase can have repercussions such as increased cost of repeated sample collection and testing, poor test turnaround times, and more seriously, delayed or incorrect diagnosis causing an exacerbation in the condition of the patient. To add to the adverse outcomes on patients, repeated testing places additional stress on laboratory resources and staff which ultimately affects every aspect of a laboratory’s daily activities.

To correctly analyse HIL interference, absorbance readings at different strategically selected wavelengths supplement the calculation of the interference indices. C56-A recommends laboratories consider several parameters when selecting an HIL interference analysis method:

Before implementing results obtained from any method detecting HIL in patient samples, it is imperative to evaluate the specificity and sensitivity of the method at a minimum of two clinically relevant concentrations. This assessment should encompass the sensitivity of the icterus index to haemoglobin and lipids, the haemolysis index to bilirubin and lipids, and the lipemic index to haemoglobin and bilirubin.

In instances of HIL interference, laboratories bear the responsibility of managing the associated results and samples. It is crucial never to utilise an HIL index for the correction of patient results. Typically, if a sample is determined to be affected by one or more of these interferences, the laboratory should reject the result and appropriately dispose of the sample. Nonetheless, in certain scenarios, threshold values can be established. For instance, haemolysis may exert a lesser impact on samples with elevated analyte concentrations. In such cases, laboratories may opt for a distinct procedure in handling these results compared to those exhibiting haemolytic interference at lower analyte concentrations.

Acusera Serum Indices Control

The Randox Acusera Serum Indices (SI) control is designed to be used to monitor an IVD instrument’s response in the detection of haemolyzed, icteric and lipemic (HIL) samples. This control can be utilised in laboratory interference testing to assist in improving error detection of pre-analytical errors affecting clinical chemistry testing. This control provides a full range of clinically relevant testing levels, including a negative (-) and three positives (+, ++ & +++).

The Randox Control offers a comprehensive solution with 3 levels for each form of interference and a negative control, providing a wider coverage compared to alternatives in the market. Our product is conveniently supplied in a lyophilized format, ensuring an extended shelf-life and ease of storage. Customers appreciate the stability of our control, as it consistently meets the 14-day open stability claims, minimizing waste and optimizing laboratory efficiency.

Typical Values

RIQAS Serum Indices External Quality Assessment

The RIQAS Serum Indices EQA programme is designed for the pre-analytical assessment of Haemolytic, Icteric and Lipemic (HIL) interferences. Available in a bi-monthly format with the option to report either quantitative or semi-quantitative results for the HIL parameters, this programme also provides an assessment on how these interferences impact on up to 25 routine chemistry parameters. This provides invaluable information on whether a correct judgement is being made to report results.

• Lyophilised for enhanced stability
• Human based serum ensuring commutable sample matrix
• Bi-monthly reporting
• HIL parameters include the option of quantitative or semi-quantitative reporting
• Interpretation of chemistry parameter results
• Submit results and view reports online via RIQAS.net

How can Randox help?

It is crucial laboratories test for haemolysis, icterus and lipemia to ensure the accuracy of their test processes are maintained. ISO 15189:2022 promotes the identification and control of non-conformities in the pre-analytical process, therefore, using Randox Serum Indices control and RIQAS Serum Indices EQA will help laboratories fulfil the requirements of the new edition of this standard.

Randox Serum Indices control displays improved consolidation, stability, and commutability to ensure laboratories are equipped to accurately determine pre-analytical interferences. Our Serum Indices control can be used with most major chemistry analysers including Roche, Abbot, Beckman, Ortho, and Siemens. When used in conjunction with Acusera 24.7, this control offers laboratories the ability to compare their HIL results with their peer group and identify potential failures in their pre-analytical process.

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