Primary care physicians' challenges in ordering clinical laboratory tests and interpreting results.

BACKGROUND: The number and complexity of clinical laboratory tests is rapidly expanding, presenting primary care physicians with challenges in accurately, efficiently, and safely ordering and interpreting diagnostic tests. The objective of this study was to identify challenges primary care physicians face related to diagnostic laboratory testing and solutions they believe are helpful and available to them. METHODS: In this study, sponsored by the Centers for Disease Control and Prevention, a random sample of general internal medicine and family medicine physicians from the American Medical Association Masterfile were surveyed in 2011. RESULTS: 1768 physicians (5.6%) responded to the survey. Physicians reported ordering diagnostic laboratory tests for an average of 31.4% of patient encounters per week. They reported uncertainty about ordering tests in 14.7% and uncertainty in interpreting results in 8.3% of these diagnostic encounters. The most common problematic challenges in ordering tests were related to the cost to patients and insurance coverage restrictions. Other challenges included different names for the same test, tests not available except as part of a test panel, and different tests included in panels with the same names. The most common problematic challenges in interpreting and using test results were not receiving the results and confusing report formats. Respondents endorsed a variety of information technology and decision support solutions to improve test selection and results interpretation, but these solutions were not widely available at the time of the survey. Physicians infrequently sought assistance or consultation from laboratory professionals but valued these consultations when they occurred. CONCLUSIONS: Primary care physicians routinely experience uncertainty and challenges in ordering and interpreting diagnostic laboratory tests. With more than 500 million primary care patient visits per year, the level of uncertainty reported in this study potentially affects 23 million patients per year and raises significant concerns about the safe and efficient use of laboratory testing resources. Improvement in information technology and clinical decision support systems and quick access to laboratory consultations may reduce physicians' uncertainty and mitigate these challenges.

Patenting carboxyformin in the United States: how does it work and what does it mean?

Carboxyformin, a new biguanide, shows promise as a treatment for type 2 diabetes mellitus (attributes assumed for the purpose of this article). But is a carboxyformin-based therapeutic formulation patentable? And if the formulation is patentable, what protection is afforded by the patent? This article examines the patent prosecution process, beginning with the initial discovery and continuing through the issuance of the patent. The article also briefly discusses issues of patent infringement and considers whether the inventor is able to practice his invention and whether he is able to keep others from the unauthorized use of his invention.

Prion interference is due to a reduction in strain-specific PrPSc levels.

When two prion strains infect a single host, one strain can interfere with the ability of the other to cause disease but it is not known whether prion replication of the second strain is also diminished. To further investigate strain interference, we infected hamsters in the sciatic nerve with the long-incubation-period transmissible mink encephalopathy (TME) agent DY TME prior to superinfection of hamsters with the short-incubation-period HY TME agent. Increases in the interval between TME agent inoculations resulted in an extension of the incubation period of HY TME or a complete block of the ability of the HY TME agent to cause disease. The sciatic nerve route of inoculation gave the two TME strains access to the same population of neurons, allowing for the potential of prion interference in the lumbar spinal cord. The ability of the DY TME agent to extend the incubation period of HY TME corresponds with detection of DY TME PrP(Sc), the abnormal isoform of the prion protein, in the lumbar spinal cord. The increased incubation period of HY TME or the inability of the HY TME agent to cause disease in the coinfected animals corresponds with a reduction in the abundance of HY TME PrP(Sc) in the lumbar spinal cord. When the two strains were not directed to the same populations of neurons within the lumbar spinal cord, interference between HY TME and DY TME did not occur. This suggests that DY TME agent replication interferes with HY TME agent replication when the two strains infect a common population of neurons.