The Value of Routine Urinalysis

The dip-stick urinalysis has been available for many years and is a simple procedure that can be performed in the doctor's office. A routine investigation should be performed with each physical examination to provide important information about how your body utilizes food, reacts to stress, and its ability to metabolize medications. It can also be a valuable screening tool for the detection of underlying medical conditions such as diabetes, kidney disease, and many other medical problems.

Urinalysis is a complete analysis of the physical and chemical properties of the urine. A random urine sample will provide the physician with a wealth of information about metabolic and organic disorders. It is a costeffective screening tool and can be interpreted within minutes with a dip-stick or chem-strip.

Typically after you have obtained a medical history from the patient, you should have the patient give you a urine sample before your physical examination. The tests on the sample may be performed by your medical assistant while you are examining the patient. The result will be waiting for you and you will be able to screen for any underlying disease processes. The information may be helpful in formulating the etiology of your final diagnosis.

A routine urine dip-stick investigation should include appearance, color, pH, glucose, protein, leukocyte esterase, nitrites, hemoglobin, and specific gravity. Some dip-stick strips will include less tests and some will be more extensive. A review of the analysis is provided as a guideline for your positive test results. As with any laboratory result, clinical correlation is necessary, as no one test stands alone.

Appearance and Color

Generally, the normal color of urine may vary from degrees of clear to dark yellow. The first specimen of the morning may be darker in color, as the body reabsorbs water as you rest, therefore concentrating the urine during sleep. Fever and hepatobiliary disease may also be a cause of darker urine. A red color may be due to gross hemorrhage along the urinary tract or from dietary intake of beets. Medications have also been know to have an effect on color, i.e., rifampin, a common antituberculosis medication, often turns all body fluids, including urine, an orangish-red color.

The appearance of urine is normally clear. Cloudy urine may be the first sign of urinary tract infection, mucus from the urinary tract, or from a stale sample allowed to sit. Cloudiness is usually attributed to the alkalinity of the urine and may not necessarily be the result of infection, which can be seen in vegetarian diets.

Urine pH

pH is registered on a scale of 1-14. The blood pH is normally in neutral territory at approximately 7.4. However, the urine usually maintains a slightly acidic environment, with a range in pH from 5-7. Variation of the level of pH may be from dietary factors such as a high protein diet (causing a more acidic environment), whereas a vegetarian diet will produce a more alkaline pH. Certain prescription medications, as well as infections and kidney disease, also tend to raise the alkaline level of urine.

Glucose

The renal threshold of glucose is approximately 180 mg/dl. At this point glucose surpasses the renal threshold and spills over into the urine. When glucose is detected in the urine a diagnosis of diabetes mellitus must be worked up. Glucosuria may also be found in patients with fever, severe stress, pregnancy, and eating large quantity of carbohydrates.

Ketones

Ketones, acetone, and beta-hydroxybutyric acid, are found in the urine when the body is metabolizing large amounts of fatty acids or with inadequate carbohydrate utilization as seen in diabetes. Ketonuria usually precedes diabetic acidosis and requires immediate attention.

Ketones may also be associated with fever, fasting and starvation diets, anorexia, high protein diets, vomiting and various G.I. disturbances.

Protein

Proteinuria is often the earliest indication of renal disease. Changes in the kidney due to renal damage results in a change in filtration properties and excretion in the urine. A temporary rise in urine protein could be caused by fever, exposure to the cold, prolonged exercise or severe emotional stress.

Most renal disease correlates with 2+ for 3+ proteinuria, whereas 4+ proteinuria is characteristic of nephrotic syndrome.

Nitrites

Nitrites are a rapid screening test for the presence of bacteria in the urine. One-hundred thousand microorganisms must be present for this reaction to occur and result in a positive test. Symptomatic patients therefore may test negative, if they don't reach this threshold.

The clean catch first morning void is usually the best sample, cue to the fact that the organisms have had a chance to multiply and will be at their greatest concentration.

Leukocytes Esterase/WBC

White blood cells are usually not present in the urine. If the patient's urine tests positive for leukocyte esterase, there is strong probability of infection. The urine should be sent to the laboratory for culture and sensitivity and the patient started on antibiotic therapy.

Hemoglobin/RBC

Red cells do not normally appear in the urine, and therefore the source of their presence must be determined. Red cells or hemoglobinuria may be associated with severe UTIs, kidney stones, burns, and hemolytic anemia. It may also be due to hemorrhagic and renal disease including renal trauma, glomerulonephritis, thrombocytopenia, cystitis and prostatitis.

Bilirubin

Large amounts of bilirubin in the urine usually suggests some form of hepatobiliary disease. Diagnostic work-up of these patients is warranted.

Specific Gravity

Specific gravity is the measurement of the kidneys ability to concentrate urine. Specific gravity will normally vary with the amount of fluid intake and the time of day the specimen was collected. Normally specific gravity is 1.023 with a range of +/-0.007.

Conditions that increase specific gravity (1.030) are: increased excretion of metabolites, as with diabetes and adrenal insufficiency; decreased plasm blood flow with CHF; and loss of body water in dehydration, diarrhea and vomiting. Decreased specific gravity (1.020) results from the loss of the kidneys ability to concentrate urine seen with renal disease (phelonephritis and glomerulonephritis) and diabetes insipidus due to the absence of antidiuretic hormone.

Summary

Doctors of chiropractic can enhance their diagnostic ability and expand their scope of practice just by including routine screening examination, such as a urinalysis on their patients. These investigation are easy to use in the office and should be performed as a routine part of every physical examination. The information obtained with this investigation may detect potentially serious organic or metabolic disorders and save the patient from chronic disease.

The thoroughness of your physical examination and laboratory investigation will instill greater patient confidence in you as their primary care physician. The patient will feel more at ease in the future about consulting their doctor of chiropractic if they feel you can handle all of the health care needs.

References

Michaels, Davida, et al. Diagnostic Procedures, The Patient and the Health Care Team. Wiley Medical Publication, New York, 1983; pp. 124-134.

Ferri FF, et al: Practical Guide to the Care of the Medical Patient, 2nd edition. Mosby Year Book, Missouri, 1991; pp 610-612.

Gomella LG, et al: Clinician's Pocket Reference, 6th edition. Appleton & Lange, Connecticut, 1989; pp 99-107.

Raymond Nanko, DC, MD
Huntington Beach, California