What should you know about blood and urine tests?

A blood sample can provide information about blood cells, inflammation, salts, sugar, organs, and how the body is responding to illness. A urine sample can show blood, protein, sugar, cells, or chemical changes. These findings may help assess problems affecting the urinary system, including a urinary tract infection, kidney infection, or benign prostatic hyperplasia. An unusual result does not identify a diagnosis by itself; medicines, hydration, timing, and collection technique can affect results.

Follow the instructions from the clinic. Some blood tests require fasting, while others do not. Tell the clinician about medicines, supplements, recent illness, and difficulty providing a sample. For urine collection, use the container supplied, avoid touching its inside, and follow directions about a midstream sample or timing. Do not stop prescribed medicine unless the clinician tells you to. Results may be discussed alongside your symptoms and examination, and treatment such as antibiotic treatment is used only when the clinical assessment supports it.

Arrange medical advice promptly for fever with pain in the side or back, visible blood in urine, confusion, repeated vomiting, or a marked reduction in urine. Seek emergency help for severe weakness, fainting, breathing difficulty, or sudden severe pain. If a test was ordered because symptoms are continuing, contact the service that arranged it if you worsen while waiting.

Ask which tests were ordered, whether you need to fast, when results should be available, and which findings need follow-up. You can also ask whether a repeat sample is needed and how your medicines might affect interpretation.