Urinalysis and laboratory tests

The urinalysis data that are usually taken is divided into two; qualitative and quantitative data from urine laboratory tests. As their names imply, qualitative tests are to test the qualities of urine, such as color, transparency, etc., while quantitative tests, try to find the amounts of some indices in urine, such as volume, specific gravity, the number of pathological components. urine (blood, protein, creatinine, etc.).

Qualitative data from urine laboratory tests.

Urine color

� On the first day of the child’s life, urine is colorless

� In the second and fourth days- dark reddish, because a large amount of urea is excreted.

� In breastfed infants, urine is almost colorless until they start drinking fruit juices and eating other foods at the age of 4-6 months

� In formula-fed infants, all children and adults, urine is yellow like straw.

Urine color changes can be physiological. For instance;

� Colorless urine is excreted when a person drinks a lot of fluids

� Urine turns orange when food contains a lot of carotene (carrot);

� Urine will be pink after eating red beets;

� Some medications influence the color of urine. So rifampicin causes the red color of urine, analginum and sulfacylamides-pink, mitroxolinum-saffron-yellow.

Certain discoloration of the urine has diagnostic value in kidney disorders:

� Dark brown urine is a pathognomic symptom of the hepatitis virus; the cause of such a color is a large number of bile pigments (hyperbilirubinuria); The characteristic sign is the formation of yellowish foam after shaking the urine.

• Smoky brown urine, which resembles tea or cola, is formed in the event of nephron damage, when red blood cells pass through the basement membrane of the glomerular capsule and lose hemoglobin. It is the main sign of acute post-streptococcal glomerulonephritis.

• A bright red color can be found when “fresh” red blood cells pass into the urine in case of trauma, renal tuberculosis, crystals, cystitis, urethritis, kidney tumor.

ï ¿½ Dark violet discoloration is a sign of considerable hemolysis of red blood cells in case of poisoning, Rh conflict, errors during blood transfusion, etc.


Urine may be cloudy only in the newborn for 2-3 days after birth. After that, every healthy person excretes clear urine. Cloudy and darkly opalescent urine may be found in case of urinary tract infection, increased amount of crystals, red blood cells or white blood cells, pus or fat in the urine.

Quantitative data from urine laboratory tests.

Diuresis means the process of producing urine. Urine volume (UV for 24 hours) is your laboratory reflection. Their meanings depend on age.

Pathological changes in urine volume.

� Polyuria is diagnosed when urine volume exceeds normal ranges by 2 times and more. It is the frequent sign of disorders with other systems (decreased cardiac edema, diabetes mellitus, diabetes insipidus). Renal polyutia develops in case of regression of nephritic edema, chronic renal failure.

ï ¿½ Oliguria means the decrease in daily urine volume at the age ranges and less. Renal oliguria is one of the most important manifestations of kidney failure. There may also be extrarenal causes of oliguria such as massive profuse bleeding, diarrhea, intoxication, heart failure, shock. It is very important to identify the reason for oliguria because the treatment plans can be quite different when the urine volume decreases less than 5% of the normal data or there is no urine for the whole day. It is one of the most dangerous conditions for a child’s life and he needs emergency medical help.

� Anuria can be

1. Renal: The kidneys do not form urine due to considerable tissue damage.

2. postrenal (mechanical): urine is produced but does not enter the bladder due to an obstruction of the upper tract or bladder neck.

� Nocturia, the normal daytime and nighttime urine volume correlation is 2: 1. This means that due to increased fluid intake and physical activity, urine excretion is more intense during the day. If the volume of nocturnal urine is greater, it is the manifestation of decreased kidney function.

Urine pH

This sign depends on age, eating habits, prescription drugs, and differs in different people, as well as in a person in different periods.

Specific gravity

It is the concentration of electrolytes and other substances that dissolve in the urine. A decrease in specific gravity can be observed in case of drinking a lot of fluids, severe kidney failure, progression of edema in the back, diabetes insipidus. An increase in Oliguria, diabetes mellitus, excretion of a marked amount of protein is observed. The excretion of 0.1 g of glucose per 11 of urine causes an increase in specific gravity by 0.004; 0.4 protein in 0.001.

Urinalysis rates that are deviations from normal are indications of metabolic disorders.

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