Quote from augigi
BSNDec06, do you have some literature about this inaccuracy?
I apologize in advance for the length of my response, but I believe that it is important for other health care professionals to have a good understanding of where medical technologists and pathologists are coming from when they show resistance to implementing POC testing...
Point of care meters are not necessarily inaccurate, but they have a greater tendency to become so because they are typically not monitored as carefully as traditional lab methods.
It is my understanding that under the Clinical Laboratory Improvement Amendments of 1998 (CLIA '88), all laboratories performing work for Meidcare must participate in a proficiency testing program. This means that they must analyze samples provided by an approved agency such as JCAHO or the College of American Pathologists on a regular basis and provide the results to the accreditation agency. If there are too many instances where a particular lab's results to not agree with their peers using the same analyzer or method, they risk losing their accreditation and must take measures to correct any problems.
Point-of-care testing is not subjected to this kind of scrutiny as a general rule. It is up to the laboratory director at each individual hospital to decide how closely POC testing is regulated. Physician office laboratories are exempt from CLIA '88 if they are performing "waived" tests, which includes most POC testing systems. This means that they may never be subjected to external review, and any problems with precision or accuracy might not be brought to light. In order to gain status as a "waived" test under CLIA '88, a laboratory testing system must be determined to be simple enough that any minimally trained worker could perform the testing with a reasonable degree of certainty that major mistakes will not be made.
Many of the studies I found state that about 80% of their results were in agreement between the laboratory and POC methods. In my opinion as a laboratorian, I see this as a problem. If I were a physician, PA or NP, I would not want to take the chance that in 20% of cases my POC method would not agree with the "gold standard" laboratory method. However, physicians must decide whether the convenience to them and the patient is worth taking this chance, and sometimes it is.
More and more laboratorians today are beginning to embrace POC testing, but we more than anyone else are aware of the potential pitfalls. So, it is important for you to understand where I am coming from and how this affects my opinion on this subject.
Here are some research articles from a Medline search:
Am J Clin Pathol. 2005 Feb;123(2):184-8
Mayo Clin Proc. 2005 Feb;80(2):181-6.
Semin Vasc Med. 2003 Aug;3(3):243-54.
Thromb Res. 2004;113(1):35-40
J Clin Anesth. 2004 Feb;16(1):7-10
J Med Assoc Thai. 2003 May;86 Suppl 1:S67-75.
Pharmacotherapy. 2002 Nov;22(11):1397-404.