Urine for Phosphorus (Phosphates)

What sample is needed for Urine Phosphorus?

1. The test sample is urine.
2. Collect urine for 24 hours.

How will you collect a 24-hour urine sample?

1. Note down the time and empty the urinary bladder.
2. Now, all the urine samples will be collected until 24 hours have passed.
3. Empty the urinary bladder when the time is finished.

What preservative will you use for urine?

1. Acidify with HCL, and If pH <3 Then, urine is stable for 6 months.
2. The vial should be washed with acid.
3. Containers should be detergent-free.
4. Instruct the patient to void the first sample and note the time.
5. After that, all the samples will be collected until 24 hours have passed.
6. Now, void the last sample in the container.
7. Refrigerate the urine sample during collection.

What are the indications for urine for Phosphorus?

1. It helps in finding kidney problems.
2. It helps to find the causes of kidney stones.
3. Phosphorus levels will give an idea about renal or bone disease.
4. Advised to assess the parathyroid function.

 How will you discuss the pathophysiology of Phosphorus?

1. Phosphorus in the body is in the form of phosphate, so phosphorus and phosphate are used interchangeably.
2. The urine phosphate test measures the amount of mineral phosphate in the urine sample collected over 24 hours.

What are the Phosphorus functions?

1. The body needs phosphate:
   1. To build and repair the bones and teeth.
   2. To help nerves function (phosphorus signaling).
   3. To help in muscle contraction.
   4. To produce energy.
   5. It helps in the synthesis of DNA and RNA.
   6. It is one of the acid-base buffers.

How is phosphorus distributed in the body?

1. 85% of the phosphate is in the bones.

1. The kidneys help control the amount of phosphate in the blood.
2. The extra amount of phosphate is excreted by the kidneys in urine.
   1. Kidneys filter phosphorus easily by the glomeruli.
   2. The proximal tubules reabsorb 85% to 90% filtered phosphorus.
   3. The parathyroid gland inhibits reabsorption, increasing phosphorus excretion.
   4. Fibroblast growth factor also increases phosphorus excretion.
3. Phosphate is a charged particle (ion) that contains the mineral phosphorus.
4. The kidneys filter the extra phosphate, passing out the body in the urine.
5. Kidney diseases can affect the phosphate level in the urine.
6. If the blood has less phosphate, it is less in the urine.
7. Eating a meal high in phosphorus will increase the phosphate level.
8. High vitamin D levels and an overactive parathyroid gland increase the phosphorus level.

 What is the normal phosphorus in urine?

Source 1

Phosphorus, inorganic in the urine:

• Constant daily diet = <1.0 g/day (<32.3 mmol/day).
• Nonrestricted diet = 0.4 to 1.31 g/day  (12.9 to 42.0 mmol/day).
  • Constant daily diet = 0.9 to 1.5 g (29 to 48 mmol) phosphorus and calcium 10 mg/kg (0.25 mmol/Kg)

Another source

• Adult = 0.4 to 1.3 grams / 24-hour urine sample.
• Calcium- and phosphate-restricted diet = < 1.0 g per 24-hour urine sample.

What are the causes of increased urine phosphate (Hyperphosphturia)?

1. Kidney diseases.
2. Hyperparathyroidism.
3. Excessive intake of vitamin D.
4. Dietary intake.

What causes decreased phosphate levels in the blood and urine (Hypophosphaturia)?

1. When the level is <2.5 mg/dL in the blood.
   1. Hypoparathyroidism.
   2. Kidney diseases.
   3. Liver diseases.
   4. Severe malnutrition.
   5. In hospitalized patients.

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