Urinalysis (Urine Culture)



The urine sample to diagnose a urinary tract infection by microscopy and seeding in a Petri dish, and, thanks to the susceptibility to guide the antibiotic treatment.


The collected urine is cultured and counted the observed colonies.

Urinalysis (urine culture)

Ideally, the material is taken to the laboratory in the morning, the patient with little drunk the night before.

After thorough disinfection of the genitourinary tract with antiseptic, the patient removes the first draft and then collects a few milliliters of urine in a sterile bottle.

In infants, the sampling is done with a plastic bag stuck to the skin.

The urine should arrive at the laboratory within two hours or stored at 4 ° C maximum.


They indicate the number of white blood cells, red blood cells and germs.

Normally, erythrocytes and leukocytes are less than 10 000 / mL.

If infection:

– Bacteriuria if> = 1 000 000 / ml;

– Leukocyturia: greater than 10,000 / mL.

Antimicrobial susceptibility testing the sensitivity of antibiotics helps guide treatment indicating by crosses or letters sensitivity antibiotics:

– From 1 to 4 cross;

– S: sensitivity; R: resistant; I: intermediate.



Practical advice:

– If the level of bacteria is between 10 2 and 10 4, and if the leukocyte count is greater than 10 000 / mL: there infection.

– If the number of bacteria is zero and the leukocyte count is greater than 10,000, it is a decapitated infection.

– If the level of bacteria is greater than 1 million and leukocyturia less than 10 000 and a second urinalysis confirms the result, there is infection.

– If the bacterium is between 10 2 and 10 4, and if the leukocyte count is less than 10,000, it is contamination by dirt, but no infection.

– If the examination can not be conducted by the laboratory on the same day, inform the patient of the ability to keep urine in the refrigerator.

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