Newcastle Laboratories

Osmolality, urine

Clinical Background:

Osmolality is a measure of the dissolved solutes in blood. The main constituents are sodium, potassium, chloride, bicarbonate, urea and glucose. Changes in water content or the major contributors w...

Osmolality is a measure of the dissolved solutes in blood. The main constituents are sodium, potassium, chloride, bicarbonate, urea and glucose. Changes in water content or the major contributors will alter osmolality in serum. Normally this would be controlled by alterations in ADH secretion and thirst to maintain serum osmolality in a tight range and results in a varying urine osmolality. When this mechanism is overridden, then changes to the serum osmolality can be seen with associated and sometimes inappropriate urine osmolality changes.

Read More

Test Details

  • Discipline:

    Biochemistry

    Biochemistry

  • Specimen Container Adult:

    Urine-Random

    Urine-Random

  • Specimen Container Paediatric:

    Urine-Random

    Urine-Random

  • Minimum Volume Adult:

    1 mL urine

    1 mL urine

  • Minimum Volume Paediatric:

    1 mL urine

    1 mL urine

  • Sample Stability:

    3 days at 20-25C

    7 days at 4-8C

    >3 months at -20C

    3 days at 20-25C

    7 days at 4-8C

    >3 months at -20C

  • Interpretation:

    Usually interpretation of urine osmolality requires knowledge of the fluid status of the patient and serum osmolality and urine sodium. Some of the causes of changes in osmolality include: diabetes...

    Usually interpretation of urine osmolality requires knowledge of the fluid status of the patient and serum osmolality and urine sodium. Some of the causes of changes in osmolality include: diabetes insipidus, SIADH, primary polydipsia, osmotic diuresis, acute renal injury, hypoadrenalism.
    For further information on interpreting osmolality please contact the duty biochemist.

    Read More
  • Reference Ranges:

    Random: 50-1200 mmol/Kg 
    (Depending on fluid intake and hydration state)

    Random: 50-1200 mmol/Kg 
    (Depending on fluid intake and hydration state)

  • Other Info:

    A Urine (plain) - 24hr sample is also acceptable

    A Urine (plain) - 24hr sample is also acceptable

  • Routine Contact Name:

    Duty biochemist

  • Routine Telephone:

    Freeman: 0191 244 8889
    RVI: 0191 282 9719

    Freeman: 0191 244 8889
    RVI: 0191 282 9719

  • Routine Email:

Availability:

All times

All sites

Turn Around:

Within 1 day

View all tests