Urine Culture and Microscopy

Urine should be tested for leucocyte esterase activity and nitrite before sending to the laboratory.

These have equivalent sensitivity and specificity for the diagnosis of UTI as microscopy. If these tests are negative, then culture is of limited value.

However:

1. urine diptests are not reliable in children under three years old. For this reason, all under three-year-olds are given a urine microscopy to look for white cells, red cells and squamous epithelial cells
2. urine diptests are not reliable in patients >65 years; if UTI is suspected please send MSU to the lab
3. do not use diptests on CSU samples; CSU samples should only be sent if patient has clinical symptoms of infection

Microscopy is only performed when any of the following are identified on the request.

• Children under three years old
  
• Glomerulonephritis
  
• SLE
  
• Endocarditis
  
• Haematuria
  
• RBCs
  
• ≥ 1+ blood on dipstick only
  
• Casts (or a diagnosis indicating cast production)
  
• Crystals
  
• Supra pubic aspirate
  
• Nephrostomy
  
• Schistosomiasis

Urine sample for Schistosomiasis

Terminal urine for investigation of Schistosomiasis must be sent no sooner than four weeks after exposure.

Samples should be collected between 10.00am and 2.00pm as this is the period of maximum activity. It is preferable to have the total urine output between these times, as this is when the most eggs are excreted.

Alternatively, a 24 hour collection of terminal samples of urine can be obtained.

Samples for Schistosomiasis investigation cannot be processed if received in boric acid.

If urine cannot be examined within an hour of collection, 1ml of undiluted formalin should be added to the sample to preserve any eggs present within the sample.

A minimum of 10ml is the ideal adequate quantity of specimen.

If processing is delayed, the sample should be refrigerated like other urine samples.

Sample type

• Bag urine
  
• Pad urine
  
• Catheter urine
  
• Clean catch urine
  
• Suprapubic aspirate
  
• Cystoscopy urine
  
• Ureteric urine
  
• Ileal conduit urine
  
• Urostomy urine
  
• Mid-stream urine
  
• Nephrostomy urine

Specimen requirements

Send in a sterile universal container

Label with specimen type and any relevant clinical details

Minimum volume

0.5ml

Frequency of test

Daily

Turnaround time

Urine culture - 2 days

Urine microscopy - one day

What to request on EPR

Urine MCS, Urine microscopy

Schistosome screen, Urine