A-Series

A-Series

1. Collecting and Preparing A Specimen

   • Note:The growth of bacteria in the long-term storage specimen may affect the test results on glucose, pH, nitrite and blood.
   • Collect a fresh urine sample in a clean and dry container. Don’t centrifuge the urine. Mix the sample well before taking the test
   • The urine test must be taken within an hour
   • All specimens must always be taken and kept under sanitary conditions.

2. Visual Reading Technique

   •  For a qualitative result, the strip should be read between 1-2 minutes after dipping.
   • Colour changes beyond 2 minutes are of no diagnostic value.
   • 1. Promptly replace cap after taking out strip
   • 2. Immerse the reagent area of the strip in the urine specimen and take it up quickly and immediately
   • 3. Run the edge of the strip against the rim of the container to remove the excess urine
   • 4. Hold the strip up horizontally and compare the result on the strip with the colour chart on the bottle label closely. Make note of the result.

3. Storage

   • The strips must be kept in the original bottle. Never use the products after the expiration date. Every strip can be used only once. Do not remove the desiccant(s). Don’t take the strips from the bottle unless it is for immediate use. Cap the bottle immediately and tightly after taking out the strips
   • Deterioration may result in discoloration or darkening of the reagent area of the strip. If all these happen, or the test results are questionable or inconsistent with the expected results, check and make sure the strips are within the expiration date and also compare with a control urine sample.

4. Reaction Principles

   • Glucose: The glucose oxidized by glucose oxidase catalyzes the formation of glucuronic acid and peroxide hydrogen. Peroxide hydrogen releases nero-ecotypes oxide (0) under the function of peroxidase. (0) oxidizes Iodide potassium, which makes the colour change.
   • Bilirubin: The direct bilirubin and dichlorobenzene diazonium produce azo dyes in a strongly acid medium.
   • Ketone: The acetoacetic acid and sodium nitroprusside cause reaction in the alkaline medium, which produces a violet colour
   • Specific Gravity: Electrolyte (M X) in the form of salt in urine reacts with poly methyl vinyl ether and malefic acid (-COOH), which are weak acid ionic exchangers. The reaction produces hydrogenous ionogen, which reacts with pH indicator that causes the colour change.
   • Blood: Haemoglobin acts as peroxidase. It can cause peroxide release neo-ecotypes oxide (O) oxidizes the indicator and makes the colour change subsequently.
   • pH: The method of the pH indicator is applied.
   • Protein: This is based on the protein-error-of-indicator principle. Anion in the specific pH indicator attracted by caution on the protein molecule makes the indicator further Ionized, which changes its colour.
   • Urobilinogen: Urobilinogen and diazonium produce pink azo dyes under the function of a strong acid medium.
   • Nitrite: Nitrite in the urine and aromatic amino sulphanilamide are diazotized to form a diazonium compound. The diazonium compound reacting with tetrahydro benzo (h) quinolin 3-phenol causes the colour change.
   • Leukocytes: Granulocyte leukocytes in urine contain esterase’s that catalyze the hydrolysis of the pyrrole amino acid ester to liberate 3-hydroxy 5-pheny pyrrole. This pyrrole reacting with diazonium forms a purple colour.

5. SPECIFIC PERFORMANCE CHARACTERISTICS

   • Each colour block or instrumental display value represents a range of values. Because of specimen and reading variability, specimens with analyte concentrations that fall between nominal levels may give results at either level.
   • Specific performance characteristics are based on clinical and analytical studies. In clinical specimens, the sensitivity depends upon several factors; the variability of colour perception, the presence or absence of inhibitory factors typically found in urine, specific gravity, pH, and the lighting conditions when the product is read visually.
   • Exact agreement between visual results and instrumental results might not be found because of the inherent differences between the perception of the human eye and the optical system of the instruments.