Mythbusting: ‘Using IQC and EQA From the Same Provider Leads to QC Bias’
Some laboratory professionals believe that using Internal Quality Control (IQC) and External Quality Assurance (EQA, also known as Proficiency Testing) material from the same provider can lead to increased levels of qc bias, or that their test system will not be appropriately challenged. It is important to address these concerns, because some labs may in fact be hindering their own performance by using IQC and EQA material from different sources.
It is important to first understand how IQC and EQA work together to help form a complete Laboratory Quality Management System.
IQC and EQA in Laboratory Quality Management
IQC is a means of monitoring test system precision on a daily basis. IQC effectively evaluates test system performance over time, so that any sudden or gradual shifts in performance can be detected. However, while IQC is an effective performance monitor, it cannot detect more intricate problems like calibration errors or wide acceptable limits provided by some QC manufacturers.
EQA is essential for challenging test system accuracy, and is carried out less frequently than IQC testing. EQA samples are tested ‘blind’ and the results are returned to the scheme organiser. As EQA testing compares an individual lab’s performance to other labs using the same method and instrument, it is a very effective tool for identification of potential issues.
Is there any disadvantage to using IQC and EQA material from the same provider?
The answer to this question depends primarily on the source material of the IQC and EQA. If an IQC provider manufactures their material using artificial additives or components of animal origin, then it will not be suitable to use EQA material from the same provider. Westgard (2011) maintains that using non-commutable IQC or EQA material can lead to results becoming compromised due to matrix effects – something which would not happen using commutable controls.
For example, with Immunoassay testing, non-human components of IQC material interact with antibodies in the reagent in a different way to fully human patient samples – ultimately giving unpredictable shifts, and not adhering to the ISO 15189 requirement to: “use quality control materials that react to the examining system in a manner as close as possible to patient samples”.
However, if the IQC and EQA material is manufactured using a source material which is similar in composition to patient samples (100% human), this commutable control will adequately mimic patient sample performance; meaning labs can use EQA and IQC material from the same provider with confidence that the integrity of their results is maintained.
ISO 15189 also states: “Use of independent third party control materials should be considered…”. In this instance, ‘Independent’ does not mean from a separate provider. It means that the QC material should not be optimized for use on one specific instrument (i.e. not dependent on a single instrument/method type).
No regulatory body states a requirement to use different providers for IQC and EQA material. Indeed, using IQC from one provider and EQA from another provider could increase the risk of labs using non-commutable material.
Labs should use commutable IQC and EQA material for a true assessment of their test system. Randox QC and RIQAS EQA are specifically designed with commutability in mind, giving labs a control which reflects patient sample performance and ensures excellent performance.
How can we help?
To learn how Randox can offer a complete solution for your laboratory, follow the links below or submit a question using the form above.
Westgard, S. (2011). Is QC Quality Compromised?. Available: https://www.westgard.com/qc-quality-compromised.htm. Last accessed 31st October 2017.
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From April 23rd to April 29th we are celebrating Medical Laboratory Professionals Week! This is a week dedicated to raising awareness for those who work in a laboratory & the hard work that goes unnoticed every day in laboratories around the world.
Have you ever wondered what happens between submitting your patient sample and receiving your results? Have you ever wondered who conducts the detailed laboratory testing for your annual check-up such as cholesterol and glucose levels? Or who analyses these results? The answer, a Medical Laboratory Professional (MLP). MLP’s provide up to 70% of the medical laboratory results for physicians and others to make informed decisions about a patient’s diagnosis and aftercare treatment plan. The work that laboratory professionals do each and every day is integral to providing excellent patient care. They perform and interpret billions of laboratory tests every year.
Providing accurate and reliable test results is of the utmost importance for laboratory professionals and also for us at Randox. With a passion for Quality Control, and with more than 30 years’ experience developing Laboratory QC for the in vitro diagnostics market, we believe in producing high quality material designed to streamline procedures, whilst reducing costs in laboratories of all sizes and budgets. These qualities have been reflected in our Acusera true third party quality controls, Acusera 24.7 interlaboratory data management software, Acusera Verify Calibration Verification material and RIQAS, the largest international EQA scheme.
Randox Quality Control would like to take this opportunity to thank all the laboratory professionals around the world and especially our own laboratory staff – you truly are the “Unsung Heroes of Healthcare”.
Today, June 27th, sees the beginning of one of the four tennis majors – Wimbledon. Basking in the summer sun while lying on ‘Henman Hill’, this yearly tournament attracts spectators from all over the globe who want to watch the world’s best tennis players ply their skills on the revered centre court over the course of a two week period. But what exactly is the most important skill a tennis player can utilise? Well, many players have different strengths but the one skill that all of them must possess is the ability to serve – and accurately.
The ability to serve is vitally important as it allows the point to begin, serving accurately however allows the player to set the pace and ensure they are on the front foot. By making sure they serve more accurately, the player can be confident in their ability to win the point and the match.
Just like tennis, laboratories will aim to be accurate when ‘serving’ up their test results. Achieving accurate test results is what every lab strives for. With patient results on the line it is important for labs to use QC material that will assist them in obtaining the correct results, therefore keeping them clear of causing a ‘racquet’.
Randox Acusera is world renowned for delivering unbiased performance assessment. Our range of true third party controls are manufactured to the highest standard ensuring commutable samples that react to the test system in the same manner as a patient sample, ultimately allowing labs to be confident in the results they produce. Much like the serve in tennis that needs to fall within a target area, QC results should be as close as possible to the target and ideally should fall within +/- 2 SD from the mean. By falling within these limits a lab can be sure of accurate results and an acceptable performance.
Employ Acusera quality controls in your laboratory today and experience unrivaled confidence in your test results.
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