Principles

Occult Blood - Pseudo-enzymatic test containing organic peroxide and a chromagen. The peroxidase effect of hemoglobin and myoglobin causes a color change to green. Normal urine contains no detectable amount of hemoglobin.

Urobilinogen - Based on the coupling reaction of urobilinogen with a stable diazonium salt in buffer. A pink to red color proportional to the urobilinogen concentration is generated. In normal urine, urobilinogen is usually present at concentrations up to 1 mg/dL

pH - This test contains a mixed indicator whihc assures a marked change in color between pH 5 and pH 9. the normal pH or urine can vary between 5 and 9.

Nitrite - This test is based on modified Griess reaction in which Nitrite in the urine reacts with amide to form a diazonium compound. The subsequent coupling reaction yeilds a pink color in the presence of nitrite.

Specific Gravity - Specific Gravity is physically determined by refractometry in the urine chemistry system and is not analyzed by strip chemmistry. A small flowcell is attached to a SG meter and the raw video from the linear photodiode array inside the device extends the measurement range to 1.060.

Leukocyte Peroxidase - Enzymatic test pad containing an indoxyl ester and a diazonium salt. Granulocyte esterases react with indoxyl ester and diazonium salt to generate a violet color.

Ascorbic acid - This test is based on Tilman's reaction in which the presence of ascorbic acid leads to the decolorization of the test pad from gray-blue to orange.

Ketones - Based on Legal's method in which the test pad contains sodium nitroprusside and glycine in an alkaline medium. A violet color proportional to methylketone is generated.

Protein - Based on the "protein error" of pH indicators on the green color developed from the presence of protein.

Bilirubin - Based on the coupling of bilirubin with diazonium salt in an acidic medium. A pinkish tan color proportional to bilirubin concentration is generated.

Color and Clarity - A narrow tubular flowcell equipped with a color sensor is located inside the Color and Clarity Module. When passing through the flowcell, the sample is illuminated with a white light and the color sensor used RGB photodetectors to measure the color of the sample. A second LED white light measures the amplitude of scattered light to determine clarity.

Glucose - Two step enzymatic reaction using gluocose oxidase, peroxidase, and a chromogen.