Urine Examination ✅ Flashcards
What are the advantages of urine examination?
- Simple
- Non-invasive
What is involved in urine examination?
- Visual inspection
- Urine microscopy
- Urine dipstick
What can be detected by visual inspection of urine?
- Haematuria
- Pyuria
What is the limitation of visual inspection of urine?
Other conditions can mimic the appearance
How can findings of haematuria or pyuria on visual inspection of urine be confirmed?
Urine microscopy
What can be detected on urine dipstick?
- Glucose
- Urobilinogen
- Bilirubin
- Ketones
- pH
- Specific gravity
- Haemoglobin
- Protein
- Leukocytes
- Nitrites
What does a urine dipstick positive for haemoglobin indicate?
Usually that there is blood in th eurine
How can haematuria be confirmed?
By the finding of red blood cells on urine microscopy
What does the absence of RBCs on urine microscopy when there is a positive dipstick for haemoglobin suggest?
Either haemoglobinuria or myoglobinuria
What is the limitation of the detection of protein using urine dipstick?
It does not give an accurate quantitative estimation
What is required to quantify protein in the urine?
Spot urine albumin or protein:creatinine ratio, or 24 hour urine protein
In who can a 24-hour urine protein estimation be performed?
Older children
If a spot urine sample for protein is being done, when is the ideal time of day to collect this?
Morning smile
Why is a morning sample preferable for testing urine albumin or protein:creatinine ratio?
It helps exclude false positives seem in children with orthostatic proteinuria
What should be suspected in cases of significant proteinuria on dipstick with insignificant albumin on quantitative estimation?
Leak of tubular proteins, indicating tub alar damage
What are leukocytes on urine dipstick suggestive of?
UTI
What is the limitation of leukocytes on urine dipstick as a tool for diagnosing UTI?
They can be secondary to fever, so is not diagnostic
What is the advantage of using nitrites to test for UTI on dipstick?
They have a high specificity
What is the limitation of testing for nitrites on urine dipstick in the diagnosis of UTI?
Low sensitivity
Why is a positive dipstick for nitrites suggestive of a UTI?
Most pathogenic bacteria produce nitrites
When might nitrites be negative in cases of UTI?
Infants and younger children
Why might nitrites be negative in infants and younger children with UTIs?
Their increased urinary frequency does not allow sufficient time for nitrites to be produced
What is done as a result of dipstick testing being of limited use in diagnosing UTI?
Urine cultures are advisable
What is the advantage of urine cultures in UTI?
- Determines bacteriological cause and antibiotic sensitivities
- Confidently uses out UTI in children younger than 3 years
What can be identified on urine microscopy?
- Red and white blood cells
- RBC casts
What is the significance of a finding of RBC casts on urinary microscopy?
It is considered diagnostic of glomerular involvement
