Urine / chemical examination

Protein, glucose, hemoglobin, ketone bodies and bile pigments are routinely detected in urine. These components are usually found in the urine of healthy people, but in such small amounts that we do not prove them by routine tests. In various pathological conditions, their concentration in urine increases.

Test (diagnostic) strips
Detection of pathological components of urine directly at the patient's bedside or in the line of first contact with the patient enables examination using test strips.

The test strips consist of a plastic carrier on which one or more indication zones are mounted. These are manufactured in such a way that a liquid analytical reagent is sucked into a suitable material (eg special filter paper) and gently dried.

Diagnostic strips are available as monofunctional, multifunctional or special examination strips.

Monofunctional strips contain basic indication zones for semi-quantitative determination of a substance in urine. Polyfunctional strips are formed by several indication zones, enabling examination of several biochemical parameters at once. They are intended for cases where it is necessary to obtain as much information as possible about the patient's health condition, eg at various screening events. In addition to monofunctional and polyfunctional strips, there are special test strips that include combinations of two or more indication zones that are selected for a particular disease, e.g., diabetes mellitus screening strips contain a zone for glucose, ketone bodies, protein, and pH.

The following urine parameters can be determined using test strips:
 * protein;
 * glucose;
 * ketone bodies;
 * bilirubin;
 * urobilinogen;
 * hemoglobin, erythrocytes;
 * ascorbic acid;
 * leukocytes;
 * nitrite;
 * pH;
 * density.

Glucose
Glucosuria is most often accompanied by an increase in glycaemia above the so-called renal glucose threshold (around 10 mmol / l). Glucose, which normally filters through the glomerular membrane, is in such a high concentration in primitive urine that it is not enough to be resorbed in the tubules and reaches the final urine. Glucosuria with normal glycemia indicates a disorder of tubular transport mechanisms - we are talking about renal glucosuria.

Ketones
Viz též Ketolátky v moči.

Procedure for examination with diagnostic strips
We will only remove as many strips from the tube as we need immediately. Close the tube with the remaining strips immediately to protect the unused strips from moisture. We do not touch the strip indication zone with our hands. We store the strips only in the original packaging and well closed with a bag of desiccant, in the dark, in a dry place at a temperature of +2 to +30 ° C.

We immerse the strip briefly for 1-2 s in the examined urine so that all zones are wetted. Then remove the strip and remove excess urine by wiping the edge of the strip against the edge of the container. We then place it in a horizontal position to prevent mixing of reagents from the individual reagent pads. After the prescribed reaction time has elapsed, usually 60 s and for leukocytes 120 s, we evaluate.

Evaluation of the color of the reaction zones of the diagnostic strips is performed:
 * subjectively comparing the resulting coloration to the color scale on the tube label in which the strips are stored;
 * objectively using reflection photometers that measure the intensity of light of the appropriate wavelength reflected from the reaction field.

Reference
1-HOHENBERGER, E.F. and H KIMLING. Compendium urinanalysis. Urinalysis with test strip [online]. 1st edition. Mannheim : Roche Diagnostics, 2008. 105 pp. Also available from < http://www.diavant.info/diavant/servlet/MDBOutput?fileId=1392 >.

2-PLIVA-Lachema Diagnostics. PHAN® diagnostic urine test strips [online]. Last revision 2009-12-04, [cit. 2010-03-21]. < https://www.erbalachema.com/cz/ >.