IQCP: Where Are We Now?
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.
Following recommendations from recognized institutions such as ISO and CLIA, more laboratories are using third party controls than ever before. However, great care should be taken when choosing which third party control to use. A number of factors should be considered, and primarily among these is whether the control challenges the complete Clinical Range and the Medical Decision Levels. ISO 15189:2012 states that ‘The laboratory should choose concentrations of control materials wherever possible, especially at or near clinical decision values, which ensure the validity of decisions made’.
Measuring the Complete Clinical Range
It is important to assess the full clinical range of an assay i.e. the range between the lowest and highest results which can be reliably reported. In order to make sure a laboratory instrument is working across the full clinical range, a QC which covers low, normal and elevated concentrations must be used.
Question: “If the full clinical range isn’t covered by QC, how will we know whether patient results which fall outside the range of quality controls are accurately reported?”
What are Medical Decision Levels?
Medical Decision Levels (MDL) are the analyte values at which medical professionals can determine whether a patient may be suffering from a certain condition. The MDL is determined by a consensus of medical professionals and clinical research. Patients’ test results are compared to the MDL and appropriate diagnoses or medical interventions can be made.
For example, the MDL of Glucose can indicate a certain diabetic status:
|Analyte||Medical Decision Level||Diagnostic Status|
|Glucose (fasting)||<100 mg/dL||Non-Diabetic|
Many QC manufacturers ‘cut corners’ in an attempt to keep costs down, which often results in the sale of controls which do not cover the complete clinical range or vital medical decision levels. Below is an example of the Glucose concentrations present in a competitor control:
Competitor Chemistry Control Level 1 – 68 mg/dL
Competitor Chemistry Control Level 2 – 134 mg/dL
Competitor Chemistry Control Level 3 – 386 mg/dL
In the examples above, the competitor’s level 1 control covers the non-diabetic MDL, but the level 2 control is not within the ‘Pre-Diabetic’ decision range. The level 3 control is also much higher than can be expected for an elevated diabetic patient result (200 mg/dL or more).
Due to the superior manufacturing process used by Randox, QC target values are consistently within the MDL of tests. For example, the Glucose concentrations present in our Liquid Assayed Chemistry Premium Plus control are:
Level 1 – 57 mg/dL
Level 2 – 114 mg/dL
Level 3 – 236 mg/dL
The MDL for Glucose is covered by the Randox control, meaning laboratory professionals can be confident that patient results will be accurately interpreted.
Immunoassay Medical Decision Levels
Controls which cover the MDL can reduce the number of Quality Controls required by laboratories. For example, Randox Acusera Lyophilised Immunoassay Controls contain particularly low levels of TSH, Ferritin and Vitamin B12 in the Level 1 control, eliminating the need for an additional control at extra expense:
|Analyte||Medical Decision Level||Randox Level 1 IA Control||Competitor Level 1 IA Control|
|TSH||0.1 or 0.27 uU/mL||0.15uU/mL||0.37 uU/mL|
|Vitamin B12||190 pmol/L||174 pmol/L||327 pmol/L|
|Ferritin||12 ng/mL||11.1 ng/mL||49.6 ng/mL|
In this example the competitor offers an anaemia control with lower levels of TSH, Vitamin B12 and Ferritin at an additional cost. With Randox Acusera QC, only one control is required for anemia monitoring and detection.
What is Calibration Verification or Linearity?
Calibration Verification, or Linearity assessment, is becoming a fundamental element for laboratories in the USA who have access to instrumentation used in the running of patient samples.
Linearity is the ability to provide results that are directly proportional to the concentration of the analyte in the test sample. CLIA defines this as the assaying of materials of known concentrations in the same manner as a patient sample to verify the instruments linearity throughout the reportable range. By performing calibration verification a lab is assessing if their test system’s calibration is still valid and if their chosen method is linear across the full reportable range, it will also supplement their existing QC and EQA/PT by challenging a larger segment of the AMR (Analytical Measuring Range). According to CLIA, a laboratory should perform, and document, calibration verification procedures at least once every 6 months or whenever one of a number of other factors occur, for example, a complete change of reagents, major preventative maintenance or replacement of parts, new instrument validation or when their control material is highlighting unusual shifts or trends in performance.
It is commonplace for laboratories to confuse calibration verification and reportable range, so much so, that advice and guidance is continually being asked for by laboratories. In short, reportable range is one of the first characteristics that should be used as an evaluation tool whereas calibration verification should be viewed as a continual performance check.
How it works
Aside from carrying out testing twice per year, CLIA also recommend that a minimum of 3 levels are tested (although most laboratories prefer to test 5) covering the low end, mid-point and high end of the instruments reportable range. Labs should run at least 2 replicates of each level in the same way they would a patient or control sample. The results are then plotted against the target values provided, if the results obtained are within the pre-established limits then the performance is considered acceptable. The degree to which the plotted curve conforms to a straight line is a measure of system linearity.
In many cases, data reduction software is provided with the product and this can be used to automatically plot results. This software is also capable of comparing results to peer group data for troubleshooting purposes.
Our Acusera Linearity Sets and Verify data reduction software will provide laboratories the chance to test low, medium and high ranges on their instrumentation – in doing so, labs will keep in line with CLIA recommended bi-annual testing as well as ensuring their instrumentation is performing well across the full reportable range.
Designed with convenience in mind, our sets cover a wide range of clinical testing including; Cardiac Markers, Therapeutic Drugs and Specific Proteins in a liquid ready-to-use format. The varying levels and combination of unique analytes enables laboratories to consolidate testing and reduce the number of individual products required.
Complementing our Linearity sets is our data reduction software, Acusera Verify. When used in conjunction with our sets you can effectively challenge your instrument across the full reportable range while ensuring accurate and reliable patient testing. Some features of our software include easy to interpret charts for at-a-glance performance, access to real-time peer group data to enhance troubleshooting and an intuitive user interface for simple data entry.
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