Point-of-Care Testing
MedSun: Newsletter #26, July 2008

Lynn Henley, M.S., M.B.A., Patient Safety Staff, Office of Surveillance and Biometrics, Center for Devices and Radiological Health, Food and Drug Administration

Introduction

It is no secret to laboratorians that laboratory testing has changed considerably during the last twenty years. This shift is occurring in the hospital, in the physician office, and in the home. While many things have contributed to this shift, the purpose of this paper is to provide a broad overview of one segment of laboratory medicine – that is, point-of-care testing (POCT).

POCT is commonly defined as laboratory diagnostic testing performed at or near the site where clinical care is delivered. This testing is performed by using medical devices such as blood glucose monitors, critical care analyzers, urinalysis instruments, etc. Nearly one third of the entire in vitro diagnostic testing market is now comprised of POCT. Steven Gutman, M.D., M.B.A., Director of FDA’s Office of In Vitro Diagnostic Device Evaluation and Safety notes that “the laboratory medicine industry is dazzling, the technology is there, and the ability to create portable tests providing robust results at the point of care has never been greater.” (S. Gutman, personal communication, April 28, 2008) As a result the market for POCT is predicted to grow at a 9% rate compounded annually so that it is projected to be $10 billion in 2010.² This paper will provide a basic high-level overview of hospital POCT. It is the first in a series of three on the subject; the second and third papers will discuss an analysis of the types of reported POCT problems to FDA and future directions, respectively.

History

Within the last century, laboratory science has evolved tremendously as a result of improvements in testing technology, increased knowledge of disease processes, and advances in methods for establishing and evaluating test performance. Over time, laboratory testing has moved from the hospital lab, to satellite laboratories, and has now branched out to include POCT at the patient bedside in the hospital and, in some cases, for example glucose or prothrombin time testing, in the patient’s home. During the past twenty years, new technology and regulatory requirements have permitted the creation and wide adoption of POCT. ³ Advances in microchemistry (such as biosensors and whole-blood analysis), microcomputerization, miniaturization, and noninvasive testing procedures represent the technological changes resulting in smaller, handheld devices. This has led to the increase in the use of diagnostic medical devices occurring throughout the hospital.⁴

Changes in regulatory requirements have also contributed to the transfer of diagnostic testing from the laboratory to the bedside. The Clinical Laboratory Improvement Amendments of 1988 (CLIA ’88) established minimum quality standards for all laboratory testing sites in the United States. CLIA ’88 allowed for a separate category of simple testing called “waived” testing. Waived tests were exempt from standard CLIA quality control and quality assurance requirements.⁵ CLIA waived tests were described as examinations or procedures that “are cleared by the United States Food and Drug Administration (FDA) for home use; employ methodologies that are so simple and accurate as to render the likelihood of erroneous results negligible, or pose no reasonable risk or harm to the patient if the test if performed incorrectly.”⁶ The waived tests at the time included such simple tests as urine dipsticks, urine pregnancy testing, and spun hematocrits. When the regulations were developed, the extent of point-of-care testing was not completely foreseen. Waived tests now comprise an increasing number of point-of-care testing diagnostics.⁷

Under the current process, a waiver may be granted to: 1) any test listed in the regulation, 2) any test system for which the manufacturer or producer applies for waiver if that test meets the statutory criteria and the manufacturer provides scientifically valid data verifying that the waiver criteria have been met, and 3) test systems cleared by the FDA for home use.⁷ Tests in category 1 are automatically waived without review; tests in category 3 require careful review to assure the product is appropriate for over the counter use; tests in category 4 require careful review to assure they meet statutory CLIA requirements for waiver. Earlier this year, FDA published final guidance outlining the type of information needed to assure a product could be waived.

Benefits of POCT

The advancement of POCT in hospitals has been advantageous to patients and to the clinical community. Hospital-based POCT is beneficial because it rapidly delivers results to the medical practitioner and enables faster consultation with the patient, enabling the practitioner to begin treatment sooner. Because patients are usually treated more quickly, costly hospital stays may be reduced. Faster patient treatment may, in turn, lead to improved patient outcomes.⁶ One example is the use of handheld blood analyzers, which permit rapid analysis of blood gases in the critical care unit. For the critically ill patients in this unit, results received in such a manner can make treatment faster and survival more likely. In addition, patients may need to spend less time in the hospital if diagnosis is more rapid. Early diagnosis directly addresses one of the primary challenges of modern healthcare, which is improving the quality and accessibility of care while reducing costs.

Another benefit of POCT is that a smaller specimen may be needed than that needed for traditional laboratory testing.⁸ A few drops of blood or less can provide accurate results within a few minutes. This permits the use of fingersticks.¹ The fact that only a few drops of blood are needed versus a larger quantity may, for very ill or frail patient may lessen the need for blood transfusions. In addition, the specimen does not need to be transported. This may reduce preanalytic errors such as confusion between samples from several patients, as the specimen is usually handled by one person for one patient at the bedside.⁶ Furthermore, this benefit reduces the need for, and cost involved with, phlebotomy and other types of invasive sample retrieval. Many analytes are available for this type of testing, including blood gases, electrolytes, pregnancy, cardiac, and infectious disease testing (see Appendix 1).

These benefits are possible only with proper communication between laboratorians, physicians, other medical staff, and patients. The individual who reads or interprets POCT results must communicate the results in a timely fashion to the appropriate healthcare provider. Standard operating procedures must be in place so that the nurse reading the analysis at the bedside conveys the information to the appropriate department or healthcare provider. As POCT becomes more entrenched in modern healthcare, establishing procedures involving this communication will be critical.

Problems with POCT

Although there are many positive factors associated with the implementation of POCT, challenges remain with this type of testing. As in standard laboratory testing, patient safety problems arise in the preanalytic, analytic, and postanalytic processes with POCT. The greatest area of concern for laboratory testing in general resides in preanalytic and postanalytic phases of the testing process. However, with POCT the analytic phase is also important because operators often have little laboratory experience and minimum analytic skills.⁹ Problems include lack of proper testing environmental controls; failure to follow the correct test procedures; failures in instruments, reagents, or software; and failure to follow proper quality control procedures.¹⁰

Table 1. A Representative Taxonomy of POCT Laboratory Errors in Use by a Number of Laboratories with Minor Modifications.¹¹

Check ALL that apply: Preanalytic error ___ Requisition incorrect/incomplete or failure of care provider to order the correct test ___ Incorrect specimen container (e.g., blood tube) or order of draw problem ___ No specimen collected or received ___ Primary specimen tube not labeled ___ Primary specimen tube mislabeled ___ Suboptimal/ruined specimen because specimen clotted ___ Suboptimal specimen because quantity not sufficient ___ Suboptimal specimen because of fluid contamination ___ Specimen suboptimal, ruined, or inadequate for other reason ___ Data entry error when logging in a specimen ___ Other preanalytic error Analytic error ___ Human error ___ Instrument error ___ Reagent error ___ Other analytic error Postanalytic error ___ Critical (panic) results not called ___ Critical (panic) results: unable to contact provider ___ Postanalytic delay in reporting ___ Results reported to wrong provider ___ Incorrect results reported because of postanalytic data entry error ___ Incorrect results reported for other reasons ___ Failure of care provider to retrieve result ___ Misinterpretation of laboratory result by care provider ___ Other postanalytic error

Quality assurance can be maintained by strict adherence to procedure and attention to uncontrolled reagents and equipment.¹² Much of the responsibility of standardization rests with the laboratory director on the CLIA certificate. A POCT committee consisting of the laboratory director as well as healthcare practitioners from varied disciplines can assist an institution in developing procedures and monitoring those procedures for improvement. Just as documentation from multiple sites, operators, and devices needs to be coordinated, representatives from different parts of the hospital need to work together to supervise the information flow. This committee can also ensure that contamination occurs infrequently and that reagents are stored properly.¹

Operator error accounts for a large number of problems. As operators have changed from laboratorians to hospital bedside caretakers and patients, chances for error have increased. According a recent survey (2002) performed by the Centers for Medicare and Medicaid Services (CMS) on the subject of point-of-care testing, sources of medical error with POCT are routinely due to operator error. CMS observers examined test performance in 436 laboratories in eight states and found that 19% of testing personnel were neither trained nor evaluated in the performance of the assays. Furthermore, 32% of the test operators could not locate test instructions when asked. Challenges presented by the increased use of POCT may be improved by supervision of test operators’ performance, assessment of their competence, and demonstration of their proficiency.¹³ As new technologies permit the increased automation of these medical devices, the potential for operator error may decrease.¹ Automation may also help with more accurate data entry as results of POCT are transferred to patient charts and other databases.

In addition to operator error, medical device failures include malfunctions, manufacturing defects in design or development, or material problems such as product instability. ¹⁴ Malfunctions are typically evidenced by inaccurate test results. Dr. Gutman reported in 2007 that glucose meters and test strips represent the largest category of IVD products generating the highest volume of patient death-and-injury reports. He said that glucose meters top the list because of the extraordinary volume of their use, their use under environmentally diverse conditions, and the risks associated with inaccurate test results. ¹⁵ Gutman also noted, “The tension between increased access to test results and potential degradation of the quality of results is a particular challenge to both regulators and users. Fortunately, professional groups are beginning to pay attention to this challenge and to apply evidence-based technology assessment to this important product line.” (S. Gutman, personal communication, April 28, 2008) A follow-up article on adverse events reported to FDA will appear in an upcoming MedSun newsletter to more fully characterize these types of problems.

New Directions

Technological advances in POCT include miniaturized devices and wireless communication. Changes such as these will alter the manner in which doctors care for patients and patients will take on increased involvement in their own care. Electronic medical records will become an important part of POCT. Medical devices used for testing in this manner will be able to accommodate the new age of personalized medicine. A further discussion of new directions in POCT will occur in a forthcoming article.

Conclusion

POCT offers more rapid diagnosis and may offer more successful outcomes¹⁶ for the patient. Challenges for the healthcare community and the patient remain as this type of testing becomes more commonplace and as new technologies are developed. However, development of quality assurance programs can ensure that modern healthcare extracts the most benefit from these devices to improve patient outcome.

Appendix 1. A Listing of Some Types of Point-of-Care Testing Currently in Use.

Diabetes testing

--Glucose

--Ketone

--Hemoglobin A1c

Hemoglobin

Reproductive testing

--Human chorionic gonadotropin (pregnancy)

--Luteinizing hormone and Fern Test (ovulation)

--Follicle-stimulating hormone (menopause)

Renal function

--Urine dipstick

--Microalbumin

Infectious disease

--Streptococcus

--HIV

--Helicobacter pylori

--Influenza A and B

--Mononucleosis

--Respiratory syncytial virus

--Trichomonas

--pH and amines (bacterial vaginosis)

Occult blood

Drugs of abuse testing

Therapeutic drug monitoring

Lipids

--Cholesterol

--High-density lipoprotein

--Low-density lipoprotein

--Triglycerides

Cardiac Markers

--Brain natriuretic peptide (BNP, NT-proBNP)

--Troponin

Liver function

--Aspartate aminotransferase (AST)

--Alanine aminotransferase (ALT)

Coagulation (prothrombin time/international normalized ratio)

Tumor markers (bladder tumor-associated antigen)

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¹¹Astion, M. (2006). Right Patient, Wrong Sample. U.S. Department of Health and Human Services, Agency for Healthcare Research and Quality, Morbidity & Mortality Rounds on the Web, Case & Commentary, December 2006. Retrieved May 19, 2008 from http://webmm.ahrq.gov/case.aspx?caseID=142#ref2
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¹⁶Kazmierczak, S., Bleile, D., Aron, K., Mansour, M., & Kazmierczak, M. (2007, November) POCT Assessment: Implementing new instrumentation helped improve turnaround times and performance at the Oregon Heath and Science University in Portland. Advance Newsmagazine for Medical Laboratory Professionals, 1-4.


Acknowledgments are made to the following people: Ann Chappie, M.T.; Ruth A. Chesler, M.T.; Donna Engleman, R.N.; Marilyn Flack; Steven Gutman, M.D., M.B.A.; and Jill Marion, B.S.E.