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.
Got a question?
In a QC survey conducted this year, Sten Westgard reached out to more than 45,000 laboratory professionals to gain a comprehensive view of the world’s Quality Control practices. It was one of the largest surveys that have been conducted and shared publicly.
Read on as we take a summarised look at our favourite bits.
Setting control Limits
Most labs are using their actual performance to set their mean and SD, however, a large percentage of labs still use manufacturer’s ranges, peer group ranges, and other non-individual sources for SD. These ranges can typically be set wider than they would if the ranges were based on their actual mean and SD. This can result in labs releasing incorrect patient results.
Laboratories were asked if they used 2 SD control limits on all tests and it was found that a majority use 2 SD. The strict use of 2 SD can generate a high level of false rejections (9% for two controls and higher for three). This causes a high level of out-of-control events; the use of QC multi-rules is recommended.
The types of Controls used by labs
More than 60% of labs were found to be using manufacturer controls, the drawbacks of which are well known. The latest ISO standards strongly encourage the use of independent / third-party controls. Westgard speculates that this will become a mandatory requirement in the next version of ISO 15189.
Frequency of QC
The first question about frequency asked how often labs ran QC during a run. Respondents reported how often they schedule QC in their labs. Around half only run QC at the beginning of a run with labs running it throughout the day coming in close second. A small proportion of labs reported running QC at both the beginning and the end of a run.
The final, least popular option involves spacing out QC based on test volume, the most scientific method determining how many patient samples can be run between controls without raising the risk of unacceptable results.
The next question asked about the overall frequency of QC. Most labs are meeting the once-a-day minimum standard for CLIA regulations.
“QC frequency remains primarily based on the rotational speed of the earth, not driven by needs of the clinician and patient.” – Sten Westgard
QC Frequency Influences
Regulator and accreditation requirements lead the way in influencing the frequency of QC with manufacturer recommendations, and professional judgement following close behind. Only a quarter of labs use the volume of testing to guide their QC frequency and one in six look to EP23 or IQCP for guidance.
Most labs are using on-board instrument informatics to support their QC charting, followed by LIS charting programs, and peer group software.
Of significance is the number of labs using Excel spreadsheets as their primary QC tool as well as standalone QC programs or even manual graph paper. This could be due to varying technological capabilities where some locations may not have access to, or the funds to afford, informatics.
A combined third of labs are out-of-control every day. In some labs this could be the result of running such a high volume of controls that false rejections are inevitable. However, rationalising in this way can lead to ‘alert fatigue’, where users begin to ignore alert flags and stop troubleshooting.
More than a quarter of labs have an out-of-control flag every few days while another roughly one in six have just one per week. A small number of labs report having few QC flags.
Managing QC Costs
Finally, laboratories were asked about the steps they take to manage QC costs. 60% claimed that they take no steps to manage costs. One in six reduced QC frequency, one in eight switched to cheaper controls, while, worryingly, almost one in ten changed their QC rules or widened limits.
Westgard’s Global QC Survey suggests there exists many inefficient implementations of Quality Control, with plenty of room for improvement. The current state of QC is, like many aspects of healthcare, unsustainable. Labs must adopt better approaches or risk their continuing feasibility, or worse, their patient’s results.
How Randox Can Help
Westgard highlights particular issues with labs mismanaging costs, still using manufacturer controls, and setting control limits – this is where Randox comes in.
Acusera Third Party Controls offer the highest quality solution for any lab – regardless of size or budget. Designed to provide an unbiased, independent assessment of performance, our internal quality controls have not been manufactured in line with, or optimised for use with any particular reagent, method or instrument helping you to easily meet ISO 15189 recommendations. Unrivaled consolidation allows for significant cost savings.
Acusera 24•7 Live Online allows you to automatically apply multi-rules and generate charts to help with setting accurate control limits, helping you get your quality control under control.
Reference: Westgard, S (2017), The 2017 Great Global QC Survey Results
IQCP stands for Individualized Quality Control Plan, and it is an all-inclusive approach to creating a customized quality control plan for a laboratory.
IQCP focuses on assuring quality in the lab using more in-depth means than simply carrying out a certain number of QC tests at a specific frequency. Many different aspects of laboratory operations will be evaluated, such as the test system, reagents, environment, testing personnel etc.
As of January 2016, many labs in and outside the USA have implemented their IQCP’s, but what impact has this had on day-to-day operations?
In order to gauge the overall effectiveness and user-experience of implementing IQCP, Westgard QC1 conducted a survey for all IQCP participants both in the USA and globally.
Opinions were mixed regarding the effectiveness of IQCP:
- Some users found that IQCP decreased the number of QC materials required
- There is a greater emphasis on the pre and post-analytic phases of testing, thus improving process error identification
- Over half of global survey participants revealed that their IQCP identified unacceptable risk(s) in their test system, thereby creating a more robust process
- Of the labs whose IQCP’s were inspected in the USA, 96.3% were deemed adequate by the relevant regulatory bodyies
- Identification of errors can lead to additional personnel training, thereby increasing the knowledge and expertise of laboratory staff
- Due to the length of time taken to create a single IQCP, coupled with the additional expense, several survey participants found that the benefits of IQCP did not justify using so many resources in its implementation
- Many labs raised concerns regarding the availability of guidance in developing an IQCP. Participants complained that useful guidelines were not provided quickly enough, and labs had to rush their IQCP implementation.
- Several survey participants felt as though there was widespread confusion over IQCP. Participants highlighted that the volume of questions from laboratory professionals proves that IQCP was not introduced by regulatory bodies in an organized or effective manner
- Some labs surveyed voiced the opinion that IQCP evaluation needs to be more standardized, and that inspections can either be too lenient or too stringent.
As with any new system, feedback is important for further refinement. IQCP appears to be a step in the right direction for the advancement of laboratory QC. According to Westgard’s survey1, only around 30% of US respondents were satisfied, showing that labs still feel improvements need to be made. Inspectoral standardization, or more concise, straightforward guidelines on IQCP implementation could be potential improvements for regulatory bodies to consider.
We would love to know your thoughts on the subject. Send us an email at firstname.lastname@example.org.
Westgard QC. (2016).2016 IQCP Users Survey. Available: https://www.westgard.com/iqcp-user-survey-comments.htm. Last accessed 25-Oct-16.