A spot calcium-creatinine ratio test is a quick laboratory assessment that measures the levels of calcium and creatinine in a single, random urine sample rather than over a full 24 hours. By dividing the calcium concentration by the creatinine concentration, doctors can correct for how concentrated or diluted your urine is at that moment. This convenient screening tool helps quickly evaluate mineral excretion, assess potential risks for kidney stones, and monitor conditions affecting bone or parathyroid health. It serves as an efficient alternative when a full day of urine collection is unnecessary or impractical.