Urinalysis – OSCE Guide

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Urinalysis (urine dipstick testing) can occasionally show up as an OSCE station and you’ll be expected to confidently carry out the procedure. This urinalysis OSCE guide provides a clear step-by-step approach to performing urinalysis, with an included video demonstration.


Gather equipment

Gather the equipment you’ll need to perform urinalysis:

  • Alcohol gel
  • Gloves
  • Apron
  • Dipsticks
  • Urine sample
  • Paper towels
  • Gather urinalysis equipment
    Gather urinalysis equipment

Initial assessment of urine

1. Wash your hands.

2. Don an apron and gloves.

3. Confirm the patient’s details on the sample bottle are correct including their name, date of birth and hospital number.

4. Inspect the colour of the urine:

  • Straw-coloured urine: this is the normal colour of urine in a healthy, hydrated individual.
  • Dark concentrated urine: suggests the individual is dehydrated.
  • Red urine: can be caused by the presence of blood in the urine (macroscopic haematuria), porphyria, drugs such as rifampicin and certain foods (e.g. beetroot).
  • Brown urine: can be caused by the presence of bile pigments (e.g. jaundice) or myoglobin (e.g. rhabdomyolysis) in the urine. Some antimalarial medication, such as chloroquine, also cause brown discolouration of the urine.

5. Inspect the clarity of the urine:

  • Clear urine: this is normal for healthy, well-hydrated individuals.
  • Cloudy urine with sediment: may indicate urinary tract infection, renal stones, high protein content (e.g. nephrotic syndrome).
  • Frothy urine: typically associated with significant proteinuria (e.g. nephrotic syndrome).

6. Consider opening the sample pot’s cap and assessing the urine’s odour:

  • Offensive odour: suggestive of urinary tract infection.
  • Sweet odour: suggestive of glycosuria (e.g. diabetes mellitus).
  • Assessment of urinary odour is rarely performed in practice.
  • Wash hands
    Wash your hands

Dipstick testing

Procedure

1. Check the expiry date of the urinalysis dipstick.

2. Remove a dipstick from the container whilst avoiding touching the reagent squares.

3. Replace the container lid to prevent oxidisation of the remaining dipsticks.

4. Insert the dipstick into the urine sample, ensuring all reagent squares are fully immersed.

5. Remove the dipstick immediately and tap off any residual urine using the edge of the container, making sure to hold the dipstick horizontally to avoid cross-contamination of the reagent squares.

6. Lay the dipstick flat on a paper towel.

7. Use the urinalysis guide on the side of the testing strip container to interpret the findings. Different reagent squares on the strip need to be interpreted at different times, so ensure you interpret the correct test at the appropriate time interval (e.g. 60 seconds for protein).

8. Once you have interpreted all of the tests, discard the strip into the clinical waste bin along with your gloves and apron.

9. Wash your hands.

  • Urinalysis
    Check the urine dipstick expiry date

Interpretation

The following tests are ordered by the time at which the reagent square should be interpreted.

Glucose

Glucose is a water-soluble sugar molecule and its presence in the urine is known as glycosuria:

  • Time at which the reagent square should be interpreted: 30 seconds
  • The absence of glucose in the urine is normal.
  • Causes of glycosuria include diabetes mellitus, renal tubular disease and some diabetic medications (e.g. SGLT2 inhibitors).

Bilirubin

Conjugated bilirubin is a water-soluble yellow pigment:

  • Time at which the reagent square should be interpreted: 30 seconds
  • The absence of bilirubin in the urine is normal.
  • The presence of bilirubin in the urine suggests increased serum levels of conjugated bilirubin, which can occur in conditions such as biliary obstruction (e.g. pancreatic cancer).

Ketones

Ketones are a breakdown product of fatty acid metabolism:

  • Time at which the reagent square should be interpreted: 40 seconds
  • The absence of ketones in the urine is normal.
  • The presence of ketones in the urine suggests increased fatty acid metabolism, which occurs during starvation and in conditions such as diabetic ketoacidosis.

Specific gravity

The specific gravity reagent square indicates the amount of solute dissolved in the urine:

  • Normal range: 1.002 – 1.035 mOsm/kg
  • Time at which the reagent square should be interpreted: 45 seconds
  • Causes of low specific gravity include conditions that result in the production of dilute urine such as diabetes insipidus and acute tubular necrosis.
  • Causes of raised specific gravity include dehydration, glycosuria (e.g. diabetes mellitus) and proteinuria (e.g. nephrotic syndrome).

pH

The pH reagent square represents the acidity of the urine:

  • Normal range: 4.5 – 8
  • Time at which the reagent square should be interpreted: 60 seconds
  • Causes of low urinary pH include starvation, diabetic ketoacidosis and other conditions that cause metabolic acidosis (e.g. sepsis).
  • Causes of raised urinary pH include urinary tract infection, conditions that cause metabolic alkalosis (e.g. vomiting) and medications (e.g. diuretics).

Blood

The blood reagent square indicates the amount of red blood cells, haemoglobin and myoglobin in the urine:

  • Time at which the reagent square should be interpreted: 60 seconds
  • The absence of red blood cells, haemoglobin and myoglobin in the urine is normal.
  • The presence of red blood cells, haemoglobin and myoglobin in the urine may indicate urinary tract infection, renal stones, injury to the urinary tract, myoglobinuria (rhabdomyolysis), nephritic syndrome and malignancy of the urinary tract.

Protein

The protein reagent square indicates the level of protein present in the urine (proteinuria):

  • Time at which the reagent square should be interpreted: 60 seconds
  • The absence of protein in the urine is normal.
  • Causes of proteinuria include nephrotic syndrome and chronic kidney disease.

Nitrites

Nitrites are a breakdown product of gram-negative organisms such as E.Coli:

  • Time at which the reagent square should be interpreted: 60 seconds
  • The absence of nitrites in the urine is normal.
  • The presence of nitrites in the urine is suggestive of urinary tract infection.

Urobilinogen

Urobilinogen is a byproduct of bilirubin breakdown in the intestine and it is normally excreted in the urine:

  • Normal range: 0.2 – 1.0 mg/dL
  • Time at which the reagent square should be interpreted: 60 seconds
  • The presence of increased levels of urobilinogen in the urine can be caused by haemolysis (e.g. haemolytic anaemia, malaria).
  • Low levels of urobilinogen can be caused by biliary obstruction.

Leukocyte esterase

Leukocyte esterase is an enzyme produced by neutrophils and therefore, when positive, it indicates the presence of white cells in the urine:

  • Time at which the reagent square should be interpreted: 2 minutes
  • A negative leukocyte esterase test is normal.
  • Causes of a positive leukocyte esterase include urinary tract infection and any condition that could result in haematuria.

To complete the procedure…

Summarise your findings.

Document the urinalysis results.

Suggest further investigations based on urinalysis results.

Further investigations
  • The presence of leukocytes and nitrites in the urine indicates a likely urinary tract infection. Appropriate further investigation would include microscopy and culture to identify pathogenic organisms.
  • The presence of glucose in the urine (glycosuria) is suggestive of diabetes mellitus and would warrant further investigation with capillary blood glucose and serum HbA1C.
  • The presence of glucose and ketones in the urine, in addition to low urinary pH, is suggestive of diabetic ketoacidosis and would warrant urgent admission to hospital for further investigations (e.g. serum blood glucose, venous blood gas) and treatment (e.g. insulin, glucose and potassium infusion).
  • Raised specific gravity and proteinuria is suggestive of nephrotic syndrome. Further investigations would include U&Es to assess renal function as well as microscopy and culture to rule out urinary tract infection.
  • The presence of blood in the urine would warrant further investigation to narrow the differential diagnosis. Possible further investigations could include microscopy and culture (UTI), full blood count, U&Es (glomerulonephritis), CT KUB (renal calculi) and cystoscopy (bladder malignancy).

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