Urinalysis in clinical diagnosis

Determination of urine-derived odorous compounds in a source separation sanitation system

Source separation sanitation systems have attracted more and more attention recently. However, separate urine collection and treatment could induce odor issues, especially in large scale application. In order to avoid such issues, it is necessary to monitor the odor related compounds that might be generated during urine storage. This study investigated the odorous compounds that emitted from source-separated human urine under different hydrolysis conditions. Batch experiments were conducted to investigate the effect of temperature, stale/fresh urine ratio and urine dilution on odor emissions. It was found that ammonia, dimethyl disulfide, allyl methyl sulfide and 4-heptanone were the main odorous compounds generated from human urine, with headspace concentrations hundreds of times higher than their respective odor thresholds. Furthermore, the high temperature accelerated urine hydrolysis and liquid-gas mass transfer, resulting a remarkable increase of odor emissions from the urine solution. The addition of stale urine enhanced urine hydrolysis and expedited odor emissions. On the contrary, diluted urine emitted less odorous compounds ascribed to reduced concentrations of odorant precursors. In addition, this study quantified the odor emissions and revealed the constraints of urine source separation in real-world applications. To address the odor issue, several control strategies are recommended for odor mitigation or elimination from an engineering perspective.

Looking at the Urine: The Renaissance of an Unbroken Tradition

The science of looking at the urine for diagnostic purposes, uroscopy, is as ancient as disease. Throughout history, urine, the first bodily fluid to be examined, has continuously and persistently provided medicine with an increasing body of knowledge about the workings of the inner body. For most of its history, uroscopy was a visual science; this focus peaked in the Middle Ages, when the vessel used to examine urine, the matula, became a symbol of the medical profession. Over time, the practice of uroscopy spread into the hands of quacks and apothecaries, who prescribed and sold their potions by merely looking at the urine. The consequent reformation measures of the 16th and 17th centuries coincided with the first attempts at analyzing the contents of urine. As a result, many of the chemical components now reported in metabolic profiles were first analyzed and identified in urine during the first half of the 18th century. In the process, what started as a science that bordered on divination laid the foundations of chemical analysis and spawned the disciplines of urology, endocrinology, and, after the use of urine in clearance studies, nephrology. The analytical methods and remarkable achievements of each of these disciplines have increased the value of examining urine. A renaissance of this oldest diagnostic tool of medicine is now under way in the proteomic profiling and detection of biomarkers in the urine, an approach which promises to further extend the merits of the unbroken tradition of looking at the urine.

The abnormal urinalysis

The urinalysis is one of the most commonly performed tests in pediatrics, and whether expected or incidental, abnormal findings are common. Understanding the strengths and limitations of the urinalysis allows one to maximize its use as a screening tool while avoiding expensive and unnecessary evaluations. This article reviews the significance of abnormal results on urine dipstick testing and urine microscopy. Causes of false positive and false negative results are summarized. Initial diagnostic considerations of abnormal urinalysis findings are provided where appropriate.

Diagnostic procedures for the urogenital system

In making clinical decisions concerning the urogenital system, the emergency department physician has many different diagnostic tools at his or her disposal. Choosing the appropriate diagnostic study can often be difficult. For well over a thousand years, the initial step in assessing almost any urologic condition has been to examine the urine. Thankfully, this has progressed from a gustatory approach to the modern urinalysis. There is certainly a great deal of information that may be gleaned from the urinalysis, but the physician must also be mindful of its limitations. Overuse of the urinalysis can result in unwanted and unhelpful information. Although IVP is still the study of choice in assessing the functional status of the kidney, the introduction of CT and ultrasound technology to clinical medicine has revolutionized the emergency department assessment of the urogenital tract. CT and ultrasound can help differentiate between the urologic emergencies and the various surgical conditions that can mimic them.

Laboratory instrumentation in clinical biochemistry: an historical perspective

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