Urine – 24-hour collection

24-hour urine collection can provide information on the good functioning of kidneys or the overall organism.

A 24-hour urine collection follows this process:

  • Prepare a large storage container to collect the 24-hour urine. The container may be provided by the laboratory, but you may also use an empty water bottle. You will need to transfer the urine from the collecting container to the storage container, mix it well and keep it cold.
  • Upon awakening, urinate and flush this first specimen and note the time. This is the start time of the 24-hour collection.
  • After the first flushed specimen, all urine must be saved, stored, and kept cold for 24 hours. In case of bowel movement, you must first urinate.
  • Urinate again at the same time, 24 hours after the start time, to finish the collection process.
  • Once the urine collection has been completed, the urine containers need to be taken to the lab as soon as possible.

Tests performed on a normal container
Clearance (always combined with a blood test) and assays for ions, BUN, creatinine, uric acid, proteins, etc.

Acidified 24-hour urine
Some factors require the urine to be collected in an acidic environment

  • Catecholamines, adrenalin, noradrenalin, dopamine, metanephrine, normetanephrine, VMA, HVA
  • Homovanillic acid (HVA) – vanillylmandelic acid (VMA) - In the 48 hours before the assay, avoid consuming bananas, vanilla, tea, coffee and chocolate.
  • Dopamine - homovanillic acid (HVA)
    Interference with drugs for Parkinson’s disease
  • Serotonin – 5 hydroxyindoleacetic acid (5HIAA)
    In the 48 hours before the assay, avoid consuming bananas, tomatoes, avocados, citrus fruits, dried fruit and nuts, pineapple, kiwi and prunes (foods rich in tryptophan and serotonin) – Interference with various antidepressants which inhibit reabsorption of serotonin.

Please note that a 10 ml container of concentrated hydrochloric acid is provided by the laboratory. This product is corrosive, it lets off irritating fumes. It must be kept out of the reach of children. Never use it for bacteriology.

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