What equipment do you need for urinalysis?
Alcohol gel Gloves Apron Dipsticks Urine sample Paper towels
What would you inspect about the urine sample?
- Colour
- Clarity
- Odour
What does the colour of urine indicate?
- 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.
What does the clarity of urine indicate?
- 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).
What does the odour of urine indicate?
- Offensive odour: suggestive of urinary tract infection.
2. Sweet odour: suggestive of glycosuria (e.g. diabetes mellitus).
How would you perform urine dipstick?
- Check the expiry date of the urinalysis dipstick.
- Remove a dipstick from the container whilst avoiding touching the reagent squares.
- Replace the container lid to prevent oxidisation of the remaining dipsticks.
- Insert the dipstick into the urine sample, ensuring all reagent squares are fully immersed.
- 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.
- Lay the dipstick flat on a paper towel.
- 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).
- Once you have interpreted all of the tests, discard the strip into the clinical waste bin along with your PPE.
- Wash your hands.
What parameters do you investigate with urinalysis?
- Glucose (30 secs)
- Bilirubin (30 secs)
- Ketones (40 secs)
- Specific gravity (45 secs)
- pH (60 secs)
- Blood (60 secs)
- Protein (60 secs)
- Nitrites (60 secs)
- Urobilinogen (60 secs)
- Leukocyte esterase (2 mins)
What does the glucose in urinalysis indicate?
Causes of glycosuria include diabetes mellitus, renal tubular disease and some diabetic medications (e.g. SGLT2 inhibitors).
What does the bilirubin in urinalysis indicate?
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).
What does the ketones in urinalysis indicate?
The presence of ketones in the urine suggests increased fatty acid metabolism, which occurs during starvation and in conditions such as diabetic ketoacidosis.
What does the specific gravity in urinalysis indicate?
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).
What does the pH in urinalysis indicate?
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).
What does the blood in urinalysis indicate?
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.
What does the protein in urinalysis indicate?
Causes of proteinuria include nephrotic syndrome and chronic kidney disease.
What does the nitrites in urinalysis indicate?
The presence of nitrites in the urine is suggestive of urinary tract infection.
What does the urobilinogen in urinalysis indicate?
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.
What does the leukocyte esterase in urinalysis indicate?
Causes of a positive leukocyte esterase include urinary tract infection and any condition that could result in haematuria.
What do leukocytes and nitrites in urine indicate? And what would further investigations be?
UTI
Microscopy and culture to identify pathogenic organisms
What are further investigations if urinalysis shows glucose?
Capillary blood glucose and HbA1C
What are further investigations if urinalysis shows glucose and ketones?
Urgent admission to hospital for DKA
What are further investigations if urinalysis shows raised specific gravity and protein?
Nephrotic syndrome
U%Es, microscopy and culture
What are further investigations if urinalysis shows blood?
Possible further investigations could include microscopy and culture (UTI), full blood count, U&Es (glomerulonephritis), CT KUB (renal calculi) and cystoscopy (bladder malignancy).
