Earliest Medicine

Long before there were laboratories, there were accepted practices for patient evaluation. Early health care providers (not all were physicians) attempted to determine the health status of the person under evaluation by any means possible. The diagnosis and the prescribed treatment were not always an accurate or scientifically based pronouncement. The process was motivated by a combination of altruism, vanity, greed, scientific thought, and philosophical and religious edict. This is not meant to imply that all was quackery and incantation. The procedures that had medical value are the ones that laid the foundation for legitimizing diagnostic medicine along with its subsequent support functions, one of which is the clinical laboratory.

One major obstacle that physicians faced in ancient times was that it was illegal to practice invasive procedures. The patient could be observed and touched, but the only specimens that could be taken were those that naturally passed from the body. Because of these limitations, urine has been the sample with the longest history of evaluation. There is some evidence that the Sumerians and Babylonians used urine for diagnosis as early as 4000 bce (1). The diagnosis of pregnancy was probably made by ancient Egyptians using the urine of the woman to germinate seeds (1). Hindu medicine describes the sweet taste of urine and that black ants are attracted to this urine if it is poured on the ground (2). Hippocrates (460-355 bce) described the characteristics and colors of urine from his patients and mentioned bubbles being present in urine from patients with long-standing kidney disease (2,3). Over the next 600 years, the study of urine was advanced very little. Galen (129-200 ad) wrote and taught that urine was a filtrate of blood and, as such, could indicate the type and location of illnesses (2). The teachings of these two men were the information base for urinalysis, or uroscopy as it was called, for the next 9-10 centuries.

During this time, approximately 800 AD, the first treatise on urine was written by Theophilus Protospatharius; in it is mentioned the first chemical test done on urine. Urine collected from patients with kidney disease was heated over a candle flame and became cloudy (2). Other physicians repeated the process, some substituting acid for heat, and although it took centuries before the precipitating substance was identified as protein, the association with disease had been recognized (3).

Other observations were made concerning the quality of the urine sample. The differences between morning and afternoon urine samples and factors like age, food, and medicaments exerted effects on the composition of urine. These were noted as early as the 10th century by Avacinna (2). It was realized as early as the 11th century that the first voided specimen in the morning was the best urine specimen for analysis and that when 24-h urine collections were required, they should be protected from light and heat (2).

Urinalysis continued to be such a focus of study that Gilles de corbeil developed a glass vessel (called a matula), shaped like a urinary bladder, specifically for the examination of urine. The concept was that the urine sediments and discoloration would occur in the vessel at a place that corresponded to the site of pathology in the body. These early urine vessels were among the first pieces of laboratory equipment and were so common and identifiable that they were one of the predecessors to the caduceus as the symbol of medicine.

Other tests and procedures were added to urinalysis and various aids were developed to make the process easier. One device of this type was the urine wheel. This wheel was the original color chart similar in purpose to those that accompany most modern dipstick packages. Along with matching the urine color on the wheel, there was an interpretive text included to assist in making a diagnosis (3).

Uroscopy soon took on a life of its own. Samples were sent to physicians without any explanation of the patient's complaint and it was expected that the analyzing practitioner would return a diagnosis and therapy (3). Expectedly, uroscopy was ripe for abuse and, assuredly, this happened. The prominence of the practitioner was enhanced if he was perceived as being able to do more than other uroscopists. consequently, claims were made concerning the interpretive powers of the analyst that far exceeded the limits of observation. It was during this period, when there was an opportunity to make a handsome income from urine analysis, that Joannes Actuarius began to write about the limitations of urine examination. He was one of the first to caution that urine examination, independent of how well it was done, could not be used to the exclusion of all other clinical findings (3).

It should not be inferred that uroscopy was always a questionable effort. Proteinuria, although protein as such had not been identified, nephritis, type I diabetes, hematuria, infection, concentration, and limited assessment of liver disease were all recognized through urinalysis. In most cases, it took centuries to identify the specific component in urine and its association with a disease; nevertheless, urine testing was a valuable diagnostic tool (3).

These early attempts to diagnose disease, through the study of the only practical body fluid available, gives some insight into the development of laboratory medicine. First, the progression from pure observation to the use of some elementary aids and procedures suggests that the seed of intellectual curiosity was germinating. If simple observation was useful, then employing procedures to define components was better. Second, equipment was being generated for a specific medical application. The equipment was primarily small, and portable but with such procedures as distillation, precipitation and evaporation, the need for a place to do this work was becoming an issue. A permanent site or address for the practitioner to do his laboratory work enabled patients to "send" their urine for analysis (an early precursor to the outpatient laboratory). Third, because uroscopy was becoming a routine practice, some members of the legitimate medical community were discussing the appropriate use of these procedures. This might be the first suggestion of test utilization in history.

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