Calcium in Urine Test

The calcium in urine test, also known as a urinary calcium test, is a diagnostic procedure used to measure the amount of calcium in a patient's urine.

Purpose

The primary purpose of this test is to assess the level of calcium excretion in the urine, which can help diagnose and monitor various medical conditions, including:

• Hyperparathyroidism (overactive parathyroid glands)
• Hypoparathyroidism (underactive parathyroid glands)
• Kidney stones
• Osteoporosis
• Malabsorption disorders
• Certain types of cancer, such as multiple myeloma or lymphoma

Procedure

To perform a calcium in urine test, a patient is typically required to collect a 24-hour urine sample. This involves:

• Emptying the bladder and discarding the first urine sample of the day
• Collecting all subsequent urine samples for the next 24 hours in a special container
• Returning the container to the laboratory or healthcare provider at the end of the 24-hour period

Interpretation of Results

The results of a calcium in urine test are usually reported as milligrams per 24 hours (mg/24hr) or millimoles per 24 hours (mmol/24hr). The normal range for urinary calcium excretion is typically:

• 100-300 mg/24hr (2.5-7.5 mmol/24hr) for adults
• 50-150 mg/24hr (1.25-3.75 mmol/24hr) for children and adolescents

Abnormal results may indicate an underlying medical condition, such as hypercalciuria (excessive calcium in the urine) or hypocalciuria (low calcium in the urine).

Risks and Limitations

The calcium in urine test is generally a safe and non-invasive procedure. However, there are some potential risks and limitations to consider:

• Contamination of the urine sample with external sources of calcium (e.g., food, soap, or cleaning products)
• Inaccurate results due to incomplete or inadequate urine collection
• False positives or false negatives due to laboratory errors or equipment malfunctions

Preparation and Special Considerations

To ensure accurate results, patients should:

• Avoid consuming foods high in calcium (e.g., dairy products, leafy greens) for at least 24 hours prior to the test
• Avoid taking medications that may affect calcium levels (e.g., diuretics, antacids) unless instructed by a healthcare provider
• Inform their healthcare provider about any underlying medical conditions or allergies