Potassium, 24-hr Urine
CPT Code(s):
84133
Turnaround Time:
8 hours
Specimen Requirements
Preferred Specimen:
Urine
Minimum Volume:
5.0 mL
Transport Container:
Yellow Top Urine Tube or Plastic Urine Cup
Transport Temperature:
Room Temperature
Collection Instructions:
Collect random urine without preservatives.
Rejection Criteria:
Unlabeled specimen or name discrepancy between specimen and request label; specimen in expired transport container; specimen received after prolonged delay; specimen in nonsterile or leaking container.
Stability Criteria
Room Temperature:
7 days
Refrigerated:
7 days
Frozen:
7 days
Clinical Significance
Measuring potassium levels in a 24-hour urine collection provides valuable clinical insights into various aspects of kidney function, electrolyte balance, and overall health. Here are some of the clinical significances of potassium in a 24-hour urine sample:
1. **Evaluation of Electrolyte Balance**: Potassium is a crucial electrolyte for normal cellular function, and its levels in urine reflect the balance between intake, excretion, and reabsorption. Abnormal potassium levels in a 24-hour urine collection may indicate disturbances in electrolyte balance, such as dehydration, overhydration, or certain kidney disorders.
2. **Assessment of Kidney Function**: The kidneys play a key role in maintaining potassium homeostasis by regulating its excretion and reabsorption. Abnormal potassium levels in a 24-hour urine sample can provide valuable information about kidney function and may indicate impaired renal tubular function, renal tubular disorders, or certain kidney diseases, such as acute kidney injury or chronic kidney disease.
3. **Diagnosis and Monitoring of Renal Tubular Disorders**: Conditions such as renal tubular acidosis (RTA) and Bartter syndrome are characterized by abnormalities in renal tubular function, including impaired potassium reabsorption. Measurement of potassium levels in a 24-hour urine collection can aid in the diagnosis and monitoring of these disorders.
4. **Assessment of Dietary Intake and Absorption**: Measuring potassium levels in a 24-hour urine sample can provide information about dietary potassium intake and absorption. Low urinary potassium levels may suggest inadequate dietary intake, while high urinary potassium levels may indicate excessive intake or impaired absorption.
5. **Evaluation of Acid-Base Balance**: Potassium ions are involved in acid-base regulation in the body, and abnormalities in urine potassium levels may indicate disturbances in acid-base balance, such as metabolic acidosis or alkalosis.
6. **Assessment of Hydration Status**: Potassium levels in urine can provide insights into an individual's hydration status. Low urine potassium levels may indicate dehydration, while high urine potassium levels may suggest overhydration or excessive fluid intake.
7. **Monitoring Treatment Response**: Changes in urine potassium levels over time can help assess the response to treatment for electrolyte imbalances, kidney disorders, or acid-base disturbances. Adjustments to medication, fluid intake, or dietary potassium may be necessary based on urine potassium measurements.
Overall, measuring potassium levels in a 24-hour urine collection is an important component of the comprehensive evaluation of kidney function, electrolyte balance, acid-base status, hydration status, and dietary intake in clinical practice. Interpretation of urine potassium levels should be done in conjunction with other clinical parameters and in the context of the patient's overall health status.