Different types of urine tests

Nowadays different types of urine tests can be done to find if bladder infection exists. Three types of urine tests like urinalysis (U/A), microscopic urinalysis (U/A micro) and urine culture are used.

In the doctor's office or a lab urinalysis (U/A) can be done. In the urine sample a dipstick is placed and up to ten different substances can be detected. Three important substances that show up positive during a bladder infection are: nitrite produced by bacteria, leukocyte esterase produced by white blood cells (immune cells) when the bacteria is attacked and sometimes blood appears during a bladder infection.

It takes a few minutes to do this test and depending on how strongly these substances show up, it can be interpreted in three ways: bladder infection unlikely when an infection is unlikely if the U/A is normal, bladder infection possible an infection may be present if one or two substances show up weak and bladder infection probable the probability of a bladder infection exists if two or three substances show up strong. It is possible that these substances may appear even when an infection is not present.

Microscopic urinalysis (U/A micro) is done only by a lab where under a microscope is examined a drop of urine. If an infection is present two things appear: white blood cells and bacteria that can be seen with a microscope. White blood cells can be missing or can be present in a small number in the urine. If a lot show up, the bacteria may be present. An infection could be even white blood cells or bacteria are not seen.

The most accurate test to determine for sure whether or not an infection is present is urine culture that is done only in a lab. The sample is put in an incubator and if bacteria is present in it, they will multiply and show up. The bacteria needs 24 to 48 hour to grow up enough to be detected. The results are different and they can be: no growth when bacteria doesn't appear in 48 hours and then the infection is not present, slight growth if a few bacteria grow, an infection can be, large growth when there are many of one type of bacteria grow the infection is present and contamination if several different types of bacteria show slight to large growth. In this case bacteria can exist but that can live on the skin and from mistake can arrive into the sample and in this case an infection is not real.

To interpret a contaminated sample can de difficult because if the sample was contaminated and an infection is present, the one type of bacteria that is causing the infection will be hidden by the contaminant bacteria that will overgrow. This infection will be treated or not by doctor depending on how suspicious he is. If the culture is contaminated and the U/A and micro are positive for infection only doctor can tell if an infection is present or not. In this case if the suspicion is low for infection the urine culture may be repeated for assurance.

If one type of bacteria grows in the culture, the bacteria will be exposed into the lab to a variety of antibiotics to see which ones the bacteria is sensitive too. Usually it takes one day after the culture is positive. This is important because it helps doctor to decide which antibiotic is best for the infection.

These tests are important because they help to detect infections. So a good treatment may be prescribed by doctors.