Urinary dipstick screening is a quick and easy way to reveal different diseases at an early stage. The diseases screened for include metabolic diseases such as diabetes mellitus (presence of glucose and / or ketone bodies in the urine), kidney disease sometimes following diabetes or high blood pressure (presence of protein in the urine), lesions of the urinary tract or of the prostate, for example following a tumor or a lithiasis (presence of blood in the urine) or else urinary infections (presence of leukocytes and generally of nitrites in the urine).

A urine dipstick is made of a plastic rod or a strip of paper, intended to be dipped in freshly collected urine, on which areas of chemical reagents are attached. able to change color in the presence of certain substances. The reaction is very fast. It usually takes 1 minute to get the test result.

The urine strips can be read with the naked eye. The reading of the urine strip is in fact easily interpreted thanks to a colorimetric scale system. This system makes it possible to have an idea of ​​the concentration, the presence or the absence of certain elements. For a more reliable reading, a urine dipstick reader can be used. This automatically reads and prints the results. These are said to be semi-quantitative: they are expressed either in negative, or in positive, or in scale of values.

The urine strips allow a rapid examination to be carried out, which can guide the diagnosis or the request for certain more in-depth complementary examinations. When used for multiple purposes, they allow urine to be tested for many parameters in a single examination, such as:

• leukocytes or white blood cells;
• nitrites;
• the proteins ;
• pH (acidity / alkalinity);
• red blood cells or red blood cells;
• hemoglobin;
• the density ;
• ketone bodies;
• the glucose;
• bilirubin;
• urobilinogen.

Thus, depending on the strips, 4 to more than 10 diseases can be detected, including in particular:

• diabetes: the presence of glucose in the urine should lead to a search for diabetes or an unbalanced anti-diabetic treatment. Indeed, a lack or improper use of insulin by the body leads to an increase in blood sugar levels, that is to say in the concentration of glucose in the blood. The excess glucose in the blood is then eliminated by the kidney in the urine. The presence of ketone bodies associated with glucose in the urine also suggests diabetes requiring emergency treatment;
• diseases of the liver or bile ducts: the presence of bilirubin, resulting from the degradation of red blood cells, and urobilinogen in the urine makes it possible to suspect certain liver diseases (hepatitis, cirrhosis) or a blockage of the excretion pathways bile, responsible for an abnormal increase in these bile pigments in the blood and then in the urine;
• diseases of the urinary system: the demonstration of proteins in the urine may reveal renal dysfunction, for example linked to diabetes or high blood pressure. Indeed, the presence of blood (red blood cells) in the urine suggests various diseases of the kidneys and urinary tract: stones, kidney or bladder tumors, etc. The measurement of urinary density makes it possible to assess the concentration power of the kidney and the risk of developing urolithiasis. The measurement of urinary pH makes it possible, among other things, to help identify the origin of a lithiasis and to adapt the diet of the lithiasic patient;
• urinary tract infections: the presence of leukocytes and generally nitrites in the urine means that bacteria capable of converting nitrates from food into nitrites are present in the bladder or the urinary tract. Infected urine also sometimes contains traces of blood and protein. Finally, a persistently alkaline pH may indicate a urinary tract infection.

You can test your urine yourself with a urine test strip. The process is quick and easy. To avoid distorting the results, you should:

• perform the test on an empty stomach;
• wash your hands and private parts with soap or Dakin’s solution, or even with wipes;
• eliminate the first jet of urine in the toilet;
• urinate in the vial provided with the strips without touching the upper edge;
• Thoroughly homogenize the urine by slowly turning the bottle several times;
• soak the strips for 1 second in the urine, completely moistening all the reactive areas;
• quickly drain by passing the slice of the strip on an absorbent paper to remove the excess urine;
• read the result by comparing the color obtained with the colorimetric range indicated on the packaging or on the bottle. To do this, respect the waiting period specified by the manufacturer.

Reading time for results is typically 2 minutes for leukocytes and XNUMX minute for nitrite, pH, protein, glucose, ketone bodies, urobilinogen, bilirubin, and blood.

Precautions for use

• do not use expired strips (the expiry date is indicated on the package);
• store the strips in a dry place at an ambient temperature below 30 ° C and in their original packaging;
• never reuse or cut the strips;
• urine must be freshly passed;
• urine must remain in the bladder for at least 3 hours so that bacteria, if present, have time to transform nitrates into nitrites;
• urine should not be too diluted. This means that you should not have drunk too much water before the test;
• never pour urine with a pipette on the strip;
• do not collect urine from an infant urine bag or urinary catheter.

The results of a urine dipstick can be interpreted in many ways depending on the circumstances in which it was prescribed. In general, the doctor uses it as a flag, green or red, which reassures him or warns him about the presence of a disease that should be confirmed by other examinations.

Thus, the higher the concentration of a substance – whether it is glucose, protein, blood or leukocytes – the more likely it becomes that disease is present. A normal urine dipstick also does not guarantee the absence of disease. The urine of some individuals only contains high amounts of abnormal substances at an advanced stage of the disease, while other individuals excrete abnormal substances in their urine sporadically.

On the other hand, although urine analysis is very important for detecting certain diseases, it is only a diagnosis. It must be supplemented by other analyzes to confirm or not the results obtained, such as:

• a urinary cytobacteriological examination (ECBU);
• a blood count (CBC);
• fasting blood sugar, that is, a measurement of glucose in the blood after at least 8 hours of fasting.