Urine tests or urine dipsticks are a quick and inexpensive way for doctors to obtain preliminary results from a patient if an infection or illness is present.  Urine reagent test results can provide information for carbohydrate metabolism, kidney and liver function, acid-based balance, and bacteriuria (bacteria growth in the bladder). Urinalysis tests can effectively detect glucose, blood, pH, ketone (acetoacetic acid), specific gravity, bilirubin, urobilinogen, nitrite, leukocyte, and proteins.

Urine Test Results:

• Glucose: This test is based on a double sequential enzyme reaction. One enzyme, glucose oxidase, catalyzes the formation of gluconic acid and hydrogen peroxide from the oxidation of glucose. Small amounts of glucose are normally excreted by the kidneys. Concentrations as little as 0.1g/dl glucose read either at 10 or 30 seconds, may be significantly abnormal if found consistently.
• Blood: This test is based on the pseudoperoxidase action of hemoglobin and erythrocytes which catalyzes the reaction of 3, 3’, 5, and 5’ –tetramethyl-benzidine and buffered organic peroxide. The resulting colors range from orange to yellow-green and dark green. Very high blood concentration may cause the color development to continue to dark blue.
•  pH: This test is based on the well-known double pH indicator method, where bromothymol blue and methyl red give distinguishable colors over a pH range between 5-9.
• Protein: This test is based on the protein error-of-indicator principle. At a constant pH, the development of any green color is due to the presence of protein. Colors on the scale range from yellow for a “Negative” reaction, to blue-green for a “Positive” reaction.
• Specific Gravity: This test is based on the apparent pKa change of certain pretreated polyelectrolytes in reaction to the ionic concentration. In the presence of an indicator, the colors range from dark blue or blue-green in urine of low ionic concentration to green and yellow-green in urine of higher ionic concentration. Random urine may vary in specific gravity from 1.003-1.040+. Twenty-four hour urine from normal adults with a normal level of diet and fluid intake will have a specific gravity of 0.016-1.02210. In severe renal damage, the specific gravity is fixed at 1.010, the value of the glomerular filtrate.
• Ketone: This test is based on the reaction of acetoacetic acid with sodium nitoprusside in a strongly basic medium. The colors range from beige or buff-pink color for a “Negative” reading to pink and pink-purple for a “Positive” reading. Normally, no ketones are present in urine. Detectable levels of kentone may occur in urine during physiological stress conditions, such as fasting, pregnancy, and frequent strenuous exercise.
• Bilirubin: This test is based on the coupling of bilirubin with a diazotized dichloroaniline in a strongly acid medium. The colors range from light tan to reddish-brown.
• Urobilinogen: This test is based on a modified Ehrlich reaction in which p-diethylaminobenzaldehyde reacts with urobilinogen in a strongly acid medium. Colors range from light pink to bright magenta.
• Nitrite: This test depends on the conversion of nitrate to nitrite by the action of Gram-negative bacteria in the urine. The nitrite reacts with p-arsanilic acid to form a diazonium compound in an acid medium. The diazonium compound in turn couples with 1,2,3,4-tetrahydrobenzo (h) quinolin to produce a pink color.
• Leukocytes: This test is based on the action of esterase present in leukocytes, which catalyzes the hydrolysis of an indoxyl ester derivative. The indoxyl ester liberated reacts with a diazonium salt to produce a beige-pink to purple color.
• Ascorbic Acid: This test is based on the action of a complex chelating agent with a polyvalent metal ion in its higher state and an indicator dye that can react with the metal ion in its lower state to produce a color change from blue-green to yellow.