Point-of-Care Blood Testing: More Than Simply Changing Venue

Abstract

Existing management and regulatory policies for hospital-based diagnostics assume the existence of a specific location with an appropriate equipment inventory and an identifiable cadre of personnel trained to deliver the service. Technologic advances allowing a diagnostic service to be delivered in a location other than the traditionally defined location present significant challenges concerning personnel proficiency, assurance of quality, reliability of interpretation, and cost. Traditional analysis of blood involves transporting a blood specimen to the clinical laboratory. Technologic advances in microsensors and computerization have resulted in the development of blood analyzers that can function reliably outside the clinical laboratory. Available data suggest that most US hospitals have adopted some form of ICU-based point-of-care blood testing,1Kost GJ Hague C The current and future status of critical care testing and patient monitoring.Am J Clin Pathol. 1995; 104: 2S-14SPubMed Google Scholar2Zimmerman JE Seveff MG Sun X et al.Evaluating laboratory usage in the intensive care unit: patient and institutional characteristics that influence frequency of blood sampling.Crit Care Med. 1997; 25: 737-748Crossref PubMed Scopus (70) Google Scholarraising a number of issues that are complex and ill defined. In this issue of CHEST (see page 1140), Kost and colleagues present an authoritative discussion of the regulatory, clinical, and management issues associated with point-of-care blood testing. In my opinion, this article is important for all physicians who practice in the ICU because it provides an overview of the regulatory and management issues that make point-of-care blood testing programs so difficult to establish. The authors appropriately present these issues encompassing the entire spectrum of point-of-care testing from home testing to the ICU. I believe it is appropriate to highlight and expand on some issues that are most germane to critical care practice. The Clinical Laboratory Improvement Act (CLIA) of 1967 resulted in regulations pertaining primarily to hospital laboratory facilities, equipment, personnel, and procedures. CLIA was extensively amended in 1988 to address both the technology changes that had occurred over 20 years and to regulate the quality of extrahospital clinical laboratories. Complex technical and political issues resulted in the Department of Health and Human Services taking 4 years to promulgate regulations for the new legislation. Unfortunately, point-of-care blood analysis devices were not introduced on a large scale until this 4-year process was well under way. The regulations for CLIA 1988, which established standards for the maintenance of quality control (QC), quality management (QM), and proficiency testing for the hospital-based clinical laboratory, were finalized in 1992.3Medicare, Medicaid and CLIA programs: regulations implementing the Clinical Laboratory Improvement Amendments of 1988 (CLIA).Federal Register. 1992; 57: 7002-7186PubMed Google Scholar Essentially, the regulations call for all other venues in which blood analysis takes place to adapt to the hospital-based clinical laboratory standards. This has had significant negative impact on cost and management issues pertaining to point-of-care blood testing in the hospital.4Shapiro BA Quality improvement standards for intensive care unit monitors: we must be informed and involved.Crit Care Med. 1992; 20: 1629-1630Crossref PubMed Scopus (5) Google Scholar Kost and colleagues (in their Table 3) refer to the two major point-of-care testing options as in vitro and in vivo/ex vivo testing. The latter category is of extreme interest to those caring for patients in the operating room and ICU because of the importance of the frequency of testing and blood conservation. I have previously suggested that in vitrotesting is more appropriately associated with the use of blood analyzers, whereas in vivo/ex vivotesting be categorized as blood monitors.5Shapiro BA Evaluation of blood gas monitors: performance criteria, clinical impact, and cost/benefit.Crit Care Med. 1994; 22: 546-548Crossref PubMed Scopus (8) Google Scholar6Shapiro BA Blood gas monitors: justifiable enthusiasm with a note of caution.Am J Respir Crit Care Med. 1994; 149: 850-851Crossref PubMed Scopus (10) Google ScholarLaboratory medicine traditionally defines an analyzer as a device that performs measurements on fluids, excrement, or tissue permanently removed from the body.3Medicare, Medicaid and CLIA programs: regulations implementing the Clinical Laboratory Improvement Amendments of 1988 (CLIA).Federal Register. 1992; 57: 7002-7186PubMed Google Scholar A clinical monitor is generically defined as a patient-dedicated apparatus used to measure physiologic phenomena without permanently removing body fluids, excrement, or tissue.6Shapiro BA Blood gas monitors: justifiable enthusiasm with a note of caution.Am J Respir Crit Care Med. 1994; 149: 850-851Crossref PubMed Scopus (10) Google Scholar Blood monitors have the potential for measuring many of the values that are most germane to caring for the critically ill. For example, a blood gas monitor is a device that measures pH, Pco2, and Po2 without permanently removing blood from the arterial catheter and without additional cost for multiple measurements.7Shapiro BA Cane RD Blood gas monitoring: yesterday, today and tomorrow.Crit Care Med. 1989; 17: 573-581Crossref PubMed Scopus (28) Google Scholar Although the first attempts at developing a blood gas monitor were intra-arterial (in vivo), it has been shown that the extra-arterial (ex vivo) approach is far more reliable8Shapiro BA Mahutte CK Cane RD et al.Clinical performance of a blood gas monitor: a prospective, multicenter trial.Crit Care Med. 1993; 21: 487-494Crossref PubMed Scopus (78) Google Scholar and is adaptive to numerous biosensors. It is important for critical care physicians to know that monitors are not included in the CLIA 1988 regulations, a fact that allows for significant freedom to develop nontraditional QC, QM, and proficiency standards that are specifically appropriate for the operating room and ICU.4Shapiro BA Quality improvement standards for intensive care unit monitors: we must be informed and involved.Crit Care Med. 1992; 20: 1629-1630Crossref PubMed Scopus (5) Google Scholar It is fair to state that when frequent measurements would improve patient care, blood monitors could provide the information at the least cost and with minimal blood loss.7Shapiro BA Cane RD Blood gas monitoring: yesterday, today and tomorrow.Crit Care Med. 1989; 17: 573-581Crossref PubMed Scopus (28) Google Scholar We are presently experiencing the proliferation of point-of-care blood analyzers as well as the introduction of blood monitors. The transfer of blood gas and other blood measurements germane to the critically ill from the laboratory to the ICU should have as profound an effect on critical care as did the introduction of laboratory-based blood gas analyzers more than 40 years ago. However, we must assure that these devices are reliable, consistent, and cost beneficial to avoid adoption of technology that provides more data, more cost, and questionable patient benefit. The next revision of the CLIA regulations will hopefully facilitate point-of-care blood testing in the ICU while assuring QC, QM, and proficiency. Until new regulations exist, we must function under what, at best, can be considered a cumbersome system. I recommend that everyone involved in critical care medicine read the review by Kost and colleagues and save it for future reference.