David Plaut: Off the Cuff

Test Development: Why Some Tests Fly and Others Flop

2009-11-09T19:59:00Z

Why do some diagnostic tests that seem useful to clinicians in their infancy never fully develop into stars? A number of reasons should be kept in mind when working with a new test in your laboratory or just reading an article or listening to a vendor. Let me begin with a story about a wonderful test that really never saw the light of day. Our group developed a test that would provide useful information to neonatal physicians about new born patients with increased bilirubin. They agreed the test...(read more)

Reference Range Headaches

2009-10-26T17:23:00Z

I was recently asked to give a lecture on establishing a reference range. For me, this is an easy task on paper but a difficult task to carry out. By reference range I mean that range from a low value to a high value within which most “normal” people will fall. Usually the reference range includes only those people above the lower 2.5 percent and below the upper 97.5 percent of those people tested—the 95 percent range. Thus, by definition, 5 percent of “normal” people will be excluded from the normal...(read more)

Case Studies: What's Your Dx?

2009-10-19T16:25:00Z

What's the diagnosis? Answer: diabetic ketoacidosis Another one: Answer: Non-thyroidal illness. Normal cortisol suggests no issue of the hypothalamus-pituitary-thyroid axis....(read more)

Warfarin and Dabigatran

2009-09-28T16:52:00Z

Coumadin (Warfarin) has long been used to treat patients with atrial fibrillation. There is no doubt that Coumadin reduces the risk of stroke in the patients. However, the risk of hemorrhage and systemic embolism is increased. In addition to the risk factors associated with the drug, it is difficult to use for some patients. It requires periodic measurement of prothromin time (PT, INR), which can be weekly for some. Effective use of the drug also requires diet restrictions—especially green vegatables....(read more)

PSA Progress

2009-09-21T16:21:00Z

Prostate cancer (PCa) remains the second leading cause of cancer deaths in the U.S. as in most Western societies. Most men with PCa will not die from the disease but with it. Since the mid-1980s, screening with the prostate-specific antigen (PSA) blood test has more than doubled the risk of a prostate cancer diagnosis. A decrease in prostate cancer death rates has been observed since that time, but the relative contribution of PSA testing as opposed to other factors, such as improved treatment, has...(read more)

Multitasking: Myth or Manageable?

2009-09-10T16:10:00Z

The concept of multitasking demands our attention. Is it really possible? If so, in what situations? What is known about multitasking? To begin, quite simply, there are times when multitasking clearly works--most people can walk and chew gum or carry on a conversation while cooking dinner. The reason this is possible is that both the tasks require minimal thinking on our part. Chewing gum borders on breathing--no thinking required--allowing our brain to pay attention to walking in case something...(read more)

AMI Case Study

2009-08-14T13:29:00Z

With this blog I would like to try something new by presenting an interesting case for you to ponder. Please study that data and the diagnosis and contemplate the situation before reading my comments. A 32 year old homeless male presents to the Emergency Department complaining of chest pain. He admits to the clinician of drinking excessive amounts of alcohol on a regular basis. At this time there is alcohol on his breath. His sinus rhythm is 100 and his ECG/EKG is non-diagnostic. The laboratory runs...(read more)

Losing Weight--And Not Finding It Again, Part II

2009-08-03T16:35:00Z

Obesity is recognized as a serious chronic disease, but there is pessimism about how successful treatment can be. One pessimistic view is that almost no one succeeds in long-term maintenance of weight loss. For this blog, I will define success as "individuals who have intentionally lost at least 10% of their body weight and kept it off at least one year." Last year Kruger et al. reported that adults who avoided eating at fast-food restaurants were more successful at weight loss maintenance. Adults...(read more)

Serum Biochemical Markers of Acute Pancreatitis

2009-07-30T16:59:00Z

Acute pancreatitis usually occurs as a result of alcohol abuse or bile duct obstruction. A careful review of the patient's history and appropriate laboratory studies can help the physician identify the etiology of the condition and guide management. Prompt identification of patients who need intensive care referral or subspecialty consultation is crucial. The number of serum biomarkers used to detect and assess severity and prognosis of acute pancreatitis (AP) is substantial. In recent years urinary...(read more)

An Immunotherapy Success Story: BCG and Bladder Cancer

2009-07-13T15:23:00Z

Bacillus Calmette-Guerin (BCG) therapy of bladder cancer is the most successful immunotherapy used against any established human neoplasm. Although how BCG works in the bladder is still being defined, it is clear that BCG orchestrates a vigorous immune response involving sensitized T-lymphocytes, activated macrophages and their cytokines that interact to kill and prevent growth of cancer cells. Instilled into the bladder, BCG eradicates existing tumors, reduces the frequency of tumor recurrences,...(read more)

Losing Weight--And Not Finding It Again

2009-06-17T18:28:00Z

The February 26, 2009 issue of the New England Journal of Medicine published an article comparing four diets: 1) 20 percent fat, 15 percent protein and 65 percent carbohydrates (low-fat, average-protein); 2) 20 percent fat, 25 percent protein and 55 percent carbohydrates (low-fat, high-protein); 3) 40 percent fat, 15 percent protein and 45 percent carbohydrates (high-fat, average-protein); and 4) 40 percent fat, 25 percent protein and 35 percent carbohydrates (high-fat, high-protein). Goals for all...(read more)

Utility of Lp-PLA2

2009-06-08T15:33:00Z

A number of recent studies have demonstrated a major role for inflammation in atherogenesis, the pathophysiology of vulnerable plaque and, consequently, of cardiovascular events. Circulating markers of inflammation (e.g., CRP as measured by an hs-method ) have attracted considerable interest as predictors of cardiovascular risk. High levels of lipoprotein-associated phospholipase A2 [ Lp-PLA(2)] are present in inflamed, rupture-prone plaques, and it appears that Lp-PLA(2) is released from these plaques...(read more)

Cystic Fibrosis: An Update

2009-06-01T16:26:00Z

The most common fatal genetic (inborn) disease in North American among Caucasians is cystic fibrosis (CF). Approximately 30,000 American suffer from CF and another 10 million persons are silent carriers of the defective gene. The gene that should produce a normal protein called CFTR is defective in patients with CF; the CFTR normally channels chloride ions (Cl-) out of cells, especially those in the lungs and pancreas. When the channel is blocked due to improper folding of the CFTR, Cl- cannot be...(read more)

Blood Substitutes

2009-05-27T18:59:00Z

Blood substitutes have been studied for at least 70 years; the search continues. All of the first and second generations of these replacements for human blood have been discontinued. Some of the third generation products have also been discontinued. There are a few still being studied. One of these is PolyHeme, a pyridoxylated, polymerized hemoglobin with a half-life of about 24 hours and a refrigerated shelf life longer than 12 months. Data indicate that fewer allogenic red blood cell transfusions...(read more)

Screening for Ovarian Cancer With Biomarkers: Are We There Yet?

2009-04-29T21:04:00Z

CA-125 is used mainly to monitor patients with ovarian cancer (OC), in part due to the low level of sensitivity when CA-125 is used alone. In an effort to improve the early detection of OC while keeping the number of false positives low (higher specificity), studies of other biomarkers, either alone or in combination with CA-125, are ongoing. In one such study, apolipoprotein A-1, transthyretin and transferrin were combined with CA-125 to detect early-stage mucinous tumors. This panel detected early-stage...(read more)