Inside the clinical laboratory, measures and standards help clinicians deliver accurate results
By Stacey Miller
To err is human. In healthcare settings, however, where perfection is expected, a mistake could make headline news. Errors at the patient's bedside or in the operating room may have serious consequences with the unintended death or serious injury of a patient.
Behind the scenes, inside hospital medical labs, the need to get it right is just as vital and consequential.
Writing in the journal, Clinica Chimica Acta, researchers from the University of Wisconsin Medical School note a majority of diagnoses are dependent on lab results with nearly two-thirds to three-fourths of information used in medical decisions coming from laboratory tests.1
So how can patients know the information they're being told based on lab results is correct? At The Ohio State University Wexner Medical Center (OSUWMC), ensuring accuracy in the lab is a wide-reaching goal, according to Sandra VanVranken, MS, MT(ASCP)SH, director of laboratory compliance.
"Several mechanisms are in place to ensure accuracy of clinical laboratory results," she said. "The main elements of quality assessment include trained and competent personnel, validated instrumentation, thorough policies and procedures, proficiency testing, quality control processes, robust laboratory information systems, and a well documented quality program."
The Lab's Constants
Any number of tests may need to be performed in the lab on any given day. No matter the variable under the microscope, the constants in the lab remain - the technician and equipment - and both need to be performing to their best ability.
For the equipment, depending on the test being performed, daily measures to ensure accuracy can include quality control, function checks, calibration, and preventive maintenance, VanVranken said. The medical center's laboratory information system is also programmed to detect delta failures, technical failures and critical results.
"All instrumentation utilized in the clinical laboratory undergoes a thorough method validation process," she said. "Performance specifications are defined for accuracy, precision, analytical sensitivity, analytical specificity to include interfering substances, method comparison, reportable range and establish reference interval (normal range)."
Calibration and preventive maintenance are performed on a specific schedule designated by the manufacturer or institution, or as needed.
"Quality control measures are always run and verified before performing patient testing," she added.
Other processes to verify instrument performance include carryover studies, analytic measurement range verification, instrument correlations, pipetting accuracy verification, etc.
To ensure staff members are on top of their lab game, competency assessment is completed and well documented following training, at six months, and at least annually after.
For all non-waived testing, all six elements of competency assessment must be documented for each area:
- direct observations of routine patient test performance, including patient preparation, if applicable, specimen handling, processing and testing;
- monitoring the recording and reporting of test results;
- review of intermediate test results or worksheets, quality control records, proficiency testing results, and preventive maintenance records;
- direct observations of performance of instrument maintenance and function checks;
- assessment of test performance through testing previously analyzed specimens, internal blind testing samples or external proficiency testing samples; and
- assessment of problem solving skills.
At OSUWMC, a designated QI representative completes a monthly quality improvement report, as well as serves on the Quality Improvement Committee. Each laboratory evaluates specific quality improvement metrics, including but not limited to: turnaround times, quality control documentation, critical value documentation, corrected reports, etc.
Government oversight also plays a key role in ensuring laboratories are able to deliver accurate results.
In 1988, Congress passed the Clinical Laboratory Improvement Amendments (CLIA). According to the American Association for Clinical Chemistry (AACC), the law requires labs undergo regular inspections every 2 years.
"Several particularly important areas for inspection are leadership, personnel training and competency requirements, proficiency testing, performance improvement, and quality control requirements," the association reports.2
CLIA requires the person performing laboratory tests be certified in his or her profession and some states require additional continuing education.
To ensure oversight on the actual tests the lab performs, CLIA requires an outside lab that has been approved by the federal government check on accuracy by sending their own samples to be tested.
"The outside agency knows the levels of the substances, or analytes, contained in the samples - the sodium level, for example - but the laboratory does not," says the AACC. "Proficiency testing includes samples for each specialty and subspecialty area in which the laboratory performs testing. The laboratory must test the samples the same way it would test patients' specimens. The outside agency uses PT to grade the laboratory's accuracy. Laboratory inspectors verify that the lab has an acceptable score in an approved PT program."
As another protective measure, clinical labs are required to test "control" samples along with the patient samples.
"The control samples contain high and low concentrations of the analyte being measured, to make sure the analyzer is running correctly across the range of concentrations the patient samples may contain," the AACC explains. "If the results vary from the known quantities, the [staff] know there is a problem. The problem identified must be corrected before patient testing can be reported."
Power of Accreditation
Beyond the required oversight, some labs have added another layer of protection by seeking accreditation. Most labs adhere to standards set by independent organizations like the College of American Pathologists (in OSUWMC's case), the National Accrediting Agency for Clinical Laboratory Sciences, or seek accreditation from organizations like The Joint Commission.
The Joint Commission has been evaluating and accrediting hospital laboratory services since 1979 and freestanding laboratories since 1995. The Joint Commission accredits about 1,700 organizations providing laboratory services, almost 2,500 CLIA-certified laboratories.
The Joint Commission provides labs with standards to help them provide safe and high-quality tests in terms of documentation, the laboratory environment, emergency management, human resources, infection control, leadership, national patient safety goals, and quality system assessments.
In 2012, about 21% of laboratories were not in compliance with the Quality System Assessment for Nonwaived Testing Standard that requires a process for handling and testing proficiency testing samples.3
According to John Gibson, MA, MT(ASCP), DLM, associate director, Standards Interpretations Group, The Joint Commission, one of the reasons laboratories are being cited for noncompliance is that organizations with multiple CLIA certificates are not conducting proficiency testing within the confines of the separate labs.
"If a single organization has multiple CLIA certificates, management may not draw the distinction that these are separate labs," he says. "Each lab must conduct its testing independently."
To better comply with the standard, The Joint Commission recommends labs to:
- Develop a written policy and procedure for testing of proficiency testing samples
- Educate staff
- Treat proficiency testing samples like patient samples
- Develop a method for ensuring that attestations are signed
- Assign someone to thoroughly review documentation before it is submitted
Medical laboratory measures, by and large, are very reliable. Quality of the specimen can lead to abnormal results. In those cases, questions arise of whether the specimen was collected correctly, whether it was stored correctly and handled, and whether the patient adhered to instructions before taking the test.
When errors are found, VanVranken said an incident report is filled out and the event is investigated.
"Corrected results are always called and documented," she says. "During the investigation all contributing factors are evaluated and mechanisms are put in place to prevent the error from occurring again."
Documentation is reviewed by technical supervisors to ensure the act of erring is left outside of the lab.
Stacey Miller is a freelance writer.
1. Westgard JO, Darcy T. The truth about quality: Medical usefulness and analytical reliability of laboratory tests. Clin Chim Acta 2004; 346(1): 3-11.
2. American Association of Clinical Chemistry. (2010). Lab oversight: A building block of trust. Retrieved on Oct. 2, 2013, from: http://labtestsonline.org/lab/labquality/start/2
3. The Joint Commission. 5 sure-fire methods complying with QSA.01.03.01 for laboratories. The Source 2013;11: 8.
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