Quality assurance & quality control

Quality assurance (QA) is a set of written policies and procedures that monitor every process involved before, during, and after a laboratory test - from specimen collection through reporting - so the lab produces reliable patient results. QA benefits the patient by catching errors before they cause harm, and it benefits the provider by documenting that testing was done correctly, which reduces liability for inaccurate results.

As mandated by law, QA programs monitor all aspects of laboratory activity, from specimen collection to processing, testing, and reporting steps. Programs check supplies, reagents, machinery, and actual test performance. QA includes quality control, personnel orientation, laboratory documentation, knowledge of laboratory instrumentation, and enrollment in a proficiency testing program (if the lab performs moderate- or high-complexity tests).

Definitions

Proficiency testing

An external check on QA in which an approved outside program periodically sends the laboratory unknown samples to test; the lab’s results are then compared against the results of other participating labs. CLIA-waived POLs are exempt from this requirement, but labs performing moderate- or high-complexity testing must enroll in an approved proficiency testing program.

CLIA classifies every test as waived, moderate, or high complexity, and that same complexity category defines the boundary of what a medical assistant may legally perform in the POL - an MA can run CLIA-waived tests, but moderate- and high-complexity testing carries additional personnel and proficiency-testing requirements.

The three stages of quality assurance in the laboratory

The overall process required to ensure QA in the laboratory is divided into three stages. These three stages must be applied to each test or procedure that is performed in the laboratory. If any of these steps are missed or performed incorrectly, QA has been broken.

Preanalytic stage

The preanalytic stage consists of the following actions:

1. The provider orders a test to screen, monitor, or diagnose a patient’s condition.
2. A written or electronic requisition is filled out, showing the test requested, the specimen required, and where the specimen will be tested.
3. The specimen is collected, labeled, and processed.
4. The specimen is transported to the laboratory in the POL or properly prepared for off site laboratory pickup.

Analytic stage

The analytic stage includes the following actions:

1. Instruments are maintained and calibrated.
2. Controls are run and analyzed for each test method (part of ongoing quality control).
3. The specimen is tested, and the results are compared with reference ranges.
4. The test results are logged and documented in the patient’s health record.

Postanalytic stage

The postanalytic stage consists of the following actions:

1. Specimens are properly discarded.
2. Analyses of control results are compared over time.
3. Patient reports from outside laboratories are logged or documented.
4. The provider interprets and signs all lab reports.
5. The patient is notified of the results in the office or is contacted by laboratory personnel.
6. The final report and all communication with the patient are documented in the patient’s health record.

Record keeping

Accurate record keeping is one of the key responsibilities of a medical assistant. Various formats are available to record laboratory information. Most providers document patient information and testing results in electronic health records (EHRs). Some POLs still use paper records. In the case of paper records, the primary source of documentation is the laboratory master logbook. The logbook contains a written record for each procedure performed, the patient identification number, results obtained, the date performed, and personnel initials. The results are then sent to the provider for verification.

Testing procedures

POLs are also required to have a procedure manual that describes how each test is performed and how the patient results are reported to the provider. Personnel are required to perform calibration or optics checks on laboratory instruments that use light detection or color change as part of the reaction process. An optics check is a specific type of calibration that assesses the optics of an electronic testing instrument or system.

In addition, they must run quality control or control materials each day before patient testing. Each manufacturer will include instructions for running control materials for its kit, procedure, or instrument. Quality control results must be documented and readily accessible. If errors or problems occur while completing quality control, the POL must perform and document remedial actions to correct errors or problems as they are identified. The requirement for when QC is to be done is a combination of management discretion and the manufacturer’s recommendations. It may not be daily.

Preventive maintenance

Preventive maintenance schedules must be followed and documented. Preventive maintenance is regularly scheduled care of equipment that will decrease the likelihood of failure. It is performed and documented at regular intervals while the equipment is in good working order. Preventive maintenance includes daily cleaning and adjustment, as well as replacement of parts when necessary. Each instrument should have a paper or electronic log or worksheet to record all changes, including daily maintenance details.

A preventive maintenance program for laboratory equipment includes the following duties:

• Follow the manufacturer’s instructions for calibrating instruments.
• Read and understand the instructions for routine instrument care.
• Perform all preventive maintenance specified by the manufacturer’s instructions.
• Keep spare parts available for immediate use.
• Record the name, address, and phone number of the contact person for maintenance or repair.
• Create a maintenance form, or use one provided by the manufacturer.

Quality control

A crucial step in the QA process is running quality control specimens. Quality control (QC) ensures the reliability of test results by detecting and eliminating errors before they are reported. Because patient treatment is often based on or reinforced by lab results, undetected errors can cause real harm to the patient - this is why QC monitoring matters.

Definitions

Accuracy

A measure of how close a test result is to the true value of the control material, as established by the manufacturer.

Precision

The ability to consistently reproduce the same test result.

Watch out: a set of control results can be precise - tightly clustered together - while still being inaccurate, if they consistently miss the true value. Reliable testing requires both accuracy and precision, not just one or the other.

When a series of control results show both accuracy and precision, the test is considered reliable and may be used for testing patients.

Quality control testing

Prepared QC test samples, called controls, are tested daily, along with patient samples. A normal control contains the normal level of the analyte, and an abnormal control contains a below or above normal level of the analyte being tested. Control test results must fall within a pre established range of results before patient results can be reported. Controls are usually supplied with the manufacturer’s prepackaged kits and should be analyzed at specified intervals as recommended by the manufacturer.

Internal controls are also provided in many CLIA-waived kit tests. Internal controls are part of the test cartridge, cassette, or card. These internal controls provide a mechanism for assuring that the test cartridge, cassette, or card is working properly and must meet the manufacturer’s QC standards in order to report the results.

Example: A control result falls outside range

A POL runs its daily glucose control, and the result falls outside the range printed on the manufacturer’s insert. The medical assistant withholds all patient glucose results run alongside that control, then troubleshoots - checking the control’s expiration date, repeating the control, and verifying instrument calibration - and documents the problem and the corrective action taken. Patient testing resumes only once the control result falls back within the established range.

Quality control testing examples

Examples of routine quality control testing in a POL include the following:

• Positive and negative controls supplied with pregnancy test kits are performed with each patient specimen or batch of patient specimens.
• Urinalysis dipstick controls (used for chemical examination of urine) should be checked daily before patient testing, and each time a new reagent container is opened.
• Controls for automated chemistry analyses should be performed before patient testing and at specified intervals during the day, depending on the number of tests run per day and the manufacturer’s recommendations.

Recording quality control testing

Every day that patient tests are performed, QC tests must also be performed and the results entered onto a paper or electronic graph or flow sheet. When new control materials are opened and used, the results and dates must be entered on a new flow sheet, along with the expiration dates of the controls. These records must be retained for several years; the exact number of years is determined by state law and CLIA mandates.