Quality and Point of Care Testing – Part 1

It is reported that 70% of clinical decisions are based on test results more often generated in a permanent laboratory. As technology has become more mobile, the laboratory has been miniaturized into portable testing devices. The wide –array of POCT devices include glucometers, urine readers, blood gas analzyers, and pregnancy tests. These devices (and many others) makeup Point-of-Care-Testing (POCT) and have transformed the landscape of bedside patient care.

POCT has now made critical and possibly life-impacting test results immediately available at the caregiver's hand. These results frequently influence a clinician's intervention decisions involving a particular chosen intervention. For example, the ability of emergency room physicians to have troponin results right at the bedside has been a game-changer for patients presenting with chest pain.

Beyond the emergency room, the FDA has granted Emergency Use Authorization (EUA) for COVID-19 POC testing based on the presence of the antigen or antibody. Having these tests available at the clinic or doctor's office has been critical in the quest to get the pandemic under control.

Because of the potential impact of the tests, it is critical POCT program administrators and directors understand the importance of quality across the entire POCT testing phase – pre-analytical, analytical, and post-analytical.

Pre-Analytical Quality

Education

Attention to quality begins with the personnel who will be conducting the tests. Many POC testing devices are used to conduct moderate-complex testing. Testing personnel performing moderately-complex tests are required to have at least a high-school diploma.

The person in charge of the POCT program conducting non-waived moderate-complex testing must qualify as a Technical Consultant. This means the person in charge of the program (and any other person who will assess competency) must have a Bachelor's degree in a physical, chemical, or biological science, or medical technology, or nursing and two years of laboratory training or experience.

Training

Training is another critical component of a POCT program. Despite the specific education and experience requirements for testing personnel dictated by the CLIA '88 regulations for non-waived testing, there are none regarding trainers' qualifications. Government regulations simply mandate testing personnel to be trained by appropriate trainers and for all training to be documented.

Training and maintaining competency can be a significant challenge for successful POCT programs. The constant turnover in nursing staff requires POCT program directors and coordinators to have a well-defined process to keep track of each nurse. Trainers must be mindful that most medical assistants, nurses, and clinicians do not have a lot of training in laboratory practices.

Whether serving a rural health care clinic or a large teaching hospital, POCT program administrators must maintain strict control of testing personnel's training and competency assessments. My healthcare system has over 11,000 waived (i.e., glucometers) testing operators and almost 4300 non-waived (i.e., ISTAT, Avoximeters) testing operators. It goes without saying a program of this size requires a dedicated team of qualified professionals.

Device Quality

Glucose and urine readers are waived testing devices built to be easily operated. Additionally, waived testing devices do not require any additional validation beyond what is specified by the manufacturer on installation.

However, non-waived testing devices require specific validation. Accuracy, precision, and linearity (reportable range) should be validated for each type of test cartridge before a device is put into use, on lot change, or every six months.

The manufacturer's goal for POCT devices is for them to be small, portable, and convenient. However, portability also presents an increased risk of mishandling devices and cartridges used to perform testing. Often, during the lifespan of a device, it is subject to abuse and misuse (dropped, left in the sun, spills, etc.); semi-annual validations of non-waived tests are necessary tasks to ensure the device continues to operate as expected.

Cartridge Quality

Validation of each type of non-waived test cartridge is one aspect of ensuring the quality of each POCT test result. Another facet of the quality program needing vigilance is controlling the storage temperature of test cartridges and dipsticks.

The storage temperatures of devices, cartridges, and dipsticks can negatively impact the quality of tests results. Manufacturers have strict temperature operating ranges for all instruments and supplies used to performed POC testing. Constant monitoring of storage rooms is necessary, and new expiration dates must be placed on all cartridges and dipsticks once removed from refrigerators or opened.

Specimen Quality

Specimen collection is often overlooked when evaluating a POCT program despite being an integral part of the testing process. A host of problems can result from poor or improper specimen collection techniques.

There is very little the laboratory can do to affect the quality of urine, salvia, and other non-invasive samples presented for waived testing. (The patient often collects these sample types after being given instructions from the collector.) However, the quality of samples collected by phlebotomy is highly influenced by the person's technical capabilities.

Too much pressure at a venipuncture site can result in hemolysis that will go undetected in whole blood POC testing. This can easily result in falsely elevated potassium levels. Interventions based on inaccurate test results can be costly in terms of patient care and unnecessary treatment.

Other errors in collecting, such as leaving the tourniquet on too long before collecting the sample or pulling back on a syringe too forcefully, can produce erroneous results.

Conclusion

Point of care testing has brought convenience, speed, and reliability to the patient's bedside and has become an integral part of reducing patients' length of stay in the emergency room. Numerous POCT pre-analytical activities are essential if a laboratory seeks to have a successful high-quality POCT program. Ensuring appropriate training and competency of testing personnel, completing device cartridge validation, and proper storage of supplies requires constant monitoring. Laboratories should have well-trained phlebotomists to reduce the incidence of poor sample quality.

This ends Part 1 of the series on POCT and Quality. In the next installment, we will discuss the quality aspects of analytical and post-analytical point-of-care testing.