Quality is an ongoing process, it’s a comprehensive program which analyse each and every aspect of an entire lab operation. It involves determination of quality goal, deciding whether the goal has been achieved and implementing corrective and preventive action (CAPA) if the goal has not been reached.
“Quality assurance is a total process whereby the quality of laboratory reports can be guaranteed “.
The goal of Quality assurance program is to systematically monitor and evaluate the quality and appropriateness of test results. Now the question comes that what is quality?
“Quality is the degree to which a set of inherent characteristics fulfil requirements “[ISO 9000].
Quality of any laboratory is decided by the final results reported by a laboratory and this includes a various phases. In the laboratory, quality assurance involves the entire testing process starting from patient registration, sample collection to report collection by the patient. These phases are termed a as pre examination, examination and post examination or better way we can say it as pre analytical, analytical and post analytical phases.
Pre Analytical Phase- This phase involves following activities:
- Patient registration,
- Sample collection,
- Bar coding of sample vials.
- Number of competent or trained staff available in lab.
- Specimen collection, it’s labelling and transport conditions.
- Processing of specimen (centrifugation) before testing and storage
- Sources of and types of specimen tested.
- Number of specimen tested.
- Selection of test kits and checking their expiry. Never use any expiry kit. Use older kits first before newer kits.
- Monitor the storage temperature of kits
- Checking the condition of samples collected, if it is hemolyzed, lipemic, clotted, etc. then reject the sample.
Analytical Phase- This phase involves the process of testing the samples:
- Performing the test as per the Standard operating procedure (SOP).
- Reagent preparation.
- Testing performance
- Handling of pipettes.
- Daily / Monthly/ Annually maintenance of machine (like spectrophotometer, washers, weighing machine etc), otherwise wrong instrument give wrong results.
- Correct use of reagents.
- Inclusion of internal & external Quality control in the test kit.
- Quality control monitoring.
Post Analytical Phase- This phase involves the after testing procedure:
- Results interpretation.
- Importing of value from machine to software (machine interfacing is requiring for this, where value on machine directly transferred to software and printed on report.
- Entering data manually into the laboratory information software.
- Maintaining records and machine printouts.
- Reviewing result of Quality control, before releasing the reports.
- For maintaining the overall Quality Management system of any laboratory and assuring its quality (whether the laboratory test results are accurate and reliable), one has to be very careful with these three phases as mentioned above.
Quality Management system is very crucial to a laboratory for providing the correct and accurate test’s results every time.
There are some important elements of a Quality Management System (QMS), which includes:
- Standard operating procedures((SOPs).
- Internal Quality control.
- External Quality Assurance Scheme (EQAS).
- Corrective and Preventive Action (CAPA).
Laboratory Quality Assurance program must ensure that following standards (as mentioned below) must be adopted by each and every laboratory in order to Maintain the quality of laboratory:
- A laboratory must have system in place for monitoring and evaluating the procedure for patient test management.
- Quality control – A laboratory must use internal quality control to check the precision of all the machines.
External Quality Assurance Scheme (EQAS) or proficiency testing to check the accuracy of the test result of laboratory.
- In house Comparison of test results. If a laboratory has more than one method of performing the same test, laboratory must (twice a year) evaluate and define the relationship between two method. Similarly, laboratory also can use split sampling, inter observer’s method of comparison in case of histopathology and cytopathology.
- Personnel assessment to check, evaluate the effectiveness of working of staff by doing the competency assessment.
- Improve relationship of patient information to patient test results.
- Improves laboratory internal communication within all departments such as documentation problem, breakdown issues of machine, critical value communication etc.
- Laboratory must address complaints investigation and take CAPA.
- Laboratory head along with all staff must review on monthly basis all QC data (I.e., EQAS, IQC).
- Last but not least laboratory must document all QC records and activities.
“IQC AND EQAS COMES under Analytical phase”
Internal Quality Control (Intra laboratory) IQC:
QC testing is performed within a laboratory to monitor and ensure the reliability of test results produced by the laboratory. Control materials (usually liquid controls and Lypholized samples- based on normal blood matrix) are used to monitor the test system and verify that quality patient test results have been attained. A control is a stabilized sample with a predetermined range of result values that simulates a patient sample.
Control samples are tested in the same way as patient samples. If the results from testing a control sample are not within the acceptable ranges, we assume there has been a problem in the test procedure, equipment, or the samples themselves. Patient results are not reported until the cause of the problem has been found, the problem resolved by taking Corrective action and Preventive Action (CAPA), and the controls retested to verify that everything is working normally.
Internal Quality Control Procedure:
IQC is used in daily basis in the decision to accept or reject results of patient samples and enable the lab to describe and monitor the quality of work. In the morning before running the patient samples, firstly lab has to run the controls to ensure the proper functioning of the equipment, reagents stability, storage temperature, etc. Once the result of controls passed or comes within the defined range as specified by the manufacturer, the value of control is accepted and permits the laboratory to start running the patient samples. If in any case the control value lies above or below the defined range then lab head or Quality Manager or Pathologist has to take corrective and preventive action (CAPA), and must record it somewhere that what action they have been taken.
Levy Jennings (LJ Chart) based on westgard rule. A Lab can plot the graph either manually using MS Excel or can take help of software which are specially designed for maintaining IQC Records (For example- Bio Rad Software). This chart has to be made on daily basis, lab has to enter the value of each parameter and set the Lab Mean in the software, accordingly software will tell you that whether your control value is passed or failed. The laboratory shall derive its own mean and standard deviation (SD) using a minimum of 20 data points to plot an LJ chart. The laboratory shall define its own criteria for accepting or rejecting the run and be able to justify the application.
As per NABL 112– “Two levels of QC shall be included at least once on the day of performing the test irrespective of the size of the laboratory. If the laboratory is operational 24X7, two level controls shall be run in the peak hour subsequently one level every 8 hours. The daily QC values shall be documented and LJ charts (Levey-Jennings chart) shall be plotted on a daily basis.
The laboratory shall analyse QC outliers, their causes and take immediate corrective action. The laboratory shall analyse the ‘out-of-control situation’ by applying the following steps:
- Search for recent events that could have caused changes.
- Examine environmental conditions.
- Follow manufacturer’s troubleshooting guide.
- Refer to instructions of manufacturers of equipment, reagents or QC / calibrator The laboratory shall calculate the monthly mean, SD and %CV.
The laboratory shall maintain control charts to demonstrate the stability of the analytical measuring systems Controls for some analyses such as CBC and blood gases have a short shelf life. Therefore, the laboratory mean cannot be calculated. In such situations the laboratory can use the manufacturer’s assigned mean and Standard Deviation to detect out of control values. The laboratory shall, however, calculate their imprecision as CV% from the data obtained and shall ensure that the CV% continuously remains in the acceptable range. The laboratory shall perform root cause analysis and take corrective actions as when out of control situations are detected.
External Quality Assurance Scheme (EQAS) or Inter laboratory Comparison:
“It is used to confirm results of IQC”
Permits a comparison of quality between laboratories and thus describe the “state of the art” for that area of laboratory work encompassed by the EQA Program.
In this program, same sample has been sent to various laboratories on monthly, bimonthly, quarterly or annual basis to the participating laboratories by the Proficiency Testing (PT) Provider or EQA Provider. Sample received by the laboratory must be run on routine basis like a normal patient sample by the same staff who runs the patient samples, not needed any special preparation for that. Once the sample examine note the result and send it back to the PT Provider for the assessment. After the assessment, PT Provider will provide the result, where the lab has been compared on the basis of Peer group, Mode method, method mode. If your lab value gets passed in peer group, then you don’t have to take any CAPA for that, but if it fails then your lab has to take CAPA and record the document.
Various companies or organization who are EQAS Provider are – CMC Vellore, Bio Rad, Randox, AIIMS Delhi, RML QAP, Anand Laboratories Banglore, etc.
How to participate in EQAS?
The laboratory has to fill the form available either available on website or manually hard copy and send it to the organization who is a EQAS Provider along with Prescribed Fee. Laboratory has to mention that in how many discipline they want to participate (Like, for Hematology, Biochemistry, Histopathology & Cytopathology, Microbiology & Serology). For each discipline lab has to fill the separate form and will have to submit the separate fee. EQAS Provider will accept your request and enrolled you with its program. As per the schedule EQAS Provider will send the sample on monthly, Bi-monthly, quarterly or annual basis.
For some tests, participation in PT program is not a feasible option for one or more of the following reasons:
- Non-availability of a formal national PT programme for analytes of interest.
- Only few laboratories performing the test.
- The analyte to be measured is unstable e.g. blood gases, ammonia, G6PD.
- Control material of the same matrix is not available.
- The sample is completely consumed during performance of the test (e.g. ESR).
Alternative approaches for those tests where a formal EQA is not available, the laboratory shall adopt alternative approaches to validate performance. Such alternative approaches are:
- Replicate testing.
- Examination of split samples (within the laboratory).
- Use of reference methods& materials, where available.
- Exchange of samples with other accredited laboratories.
When the laboratory exchanges samples with other laboratories as an alternative approach to EQA participation, following needs to be addressed:
- In the case of comparison between 2 laboratories, one will function as the “reference
laboratory” against which the other will be compared.
- This is to be documented as an MoU.
- When there are several laboratories, compare the result against the “reference laboratory”
The results obtained shall be compared statistically and for guidance, the laboratory may refer to the most current edition of CLSI document EP9 – Measurement Procedure Comparison and Bias Estimation Using Patient Samples.
Other quality assurance procedures which are useful in addition to IQC but do not replace split sample analysis are:
- Review of daily mean.
- Delta check.
- Clinical correlation.
- Correlation with other laboratory results.
Internal Quality Control is for Precision and External Quality Assurance System is for checking the accuracy of the result obtained by the lab but both are important parameter for maintaining the quality assurance of any Laboratory.
Quality Coordinator of St. Joseph Hospital, Lucknow, Uttar Pradesh
M.Tech (Biotechnology), Certified NABH Internal Auditor, Certified NABL Internal Auditor, Certified in Hospital Infection Control Practices.