Lab Diagnosis of Kidney Infection (Pyelonephritis)

Here are some procedures that needs to be checked to diagnose kidney infection (pyelonephritis).

The most important test in diagnosing kidney infection is urinalysis (UA). This is basically a test for analyzing urine samples and evaluating the presence of infection in the urine. Urinalysis is done by collecting middle transmit urine in sterile glass. Urine can be analyzed by a physician at the clinic or by laboratory analysis.

Because urine is usually sterile, any finding that suggests an infection may be considered abnormal and can be suspected to be kidney infection. A gross urine examination (macroscopic analysis) can show a cloudy urine color.

With dipstick urine tests, typical findings lead to urinary tract infections include positive results for esterase, nitrate, or leukocyte testing.

In microscopic urinalysis (analysis under a microscope), the presence of white blood cells, red blood cells, or bacteria in the urine strongly suggests a kidney infection.

Generally, the visualization of 100,000 bacteria in one cc (100,000 / ml) of urine samples confirms the diagnosis of urinary tract infection or kidney infection.

In some situations, bacteria with an amount less than 100,000 / ml may still be enough to make the diagnosis. If no white blood cells or bacteria are visible in the urine, other diagnoses may need to be considered.

When bacteria are present in the urine, further analysis is needed to determine the type of the bacteria. Once the exact type of bacteria is known, usually its sensitivity to typical antibiotics is also examined as a further treatment guide.

In more complicated cases, imaging studies, such as CT scans of the abdomen and pelvis, or abdominal ultrasound, may also be necessary.

Complicated kidney infections are usually associated with more severe symptoms and more significant kidney involvement, including the formation of renal abscess or gases that can be detected by CT scan or ultrasound.

Recurrent (chronic) kidney infections are common due to kidney stones or other structural abnormalities, such as prostate enlargement or long urine reflux in the ureter (vesico-ureter reflux). X-ray examination, ultrasound, or CT scan may be necessary to investigate these cases.