What colors indicate a positive UTI, and what colors indicate a negative result?

For diagnosing urinary tract infections (UTIs), urine test strips are designed to measure key parameters such as leukocytes and nitrites.

Leukocytes

When testing for leukocytes, a positive result is indicated if the test pad changes to a color darker than cream. This color change signifies the presence of white blood cells in the urine. White blood cells are crucial components of the body's immune response, and their appearance in the urine often suggests that the body is responding to an infection or inflammation. The presence of leukocytes typically indicates that the immune system is actively fighting an infection within the urinary tract or dealing with inflammation.
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Nitrites

The nitrite test on the strip shows a positive result if the test pad changes to a darker color. Nitrites are produced by specific bacteria commonly associated with UTIs. These bacteria have the ability to convert nitrates, which are normally present in urine, into nitrites. The detection of nitrites in the urine supports the diagnosis of a UTI by confirming the presence of these bacteria. The presence of nitrites, in combination with other symptoms or test results, helps in diagnosing a UTI more accurately.

A lighter color or no color change generally indicates a negative result, suggesting that neither leukocytes nor nitrites are present in significant amounts. For more detailed information on interpreting test results, you can refer to this blog.