Mid-stream urine (MSU)



  • A minimum of 2 ml of urine is required for routine analysis. Exceptions may be made for babies and renal patients. In other patients small samples will not be processed.
  • Samples are screened for pyuria and bacteruria by an automated image analysis system. Samples with no detectable pyuria and bacteruria are reported as negative and are not routinely cultured.
  • Certain samples are routinely cultured regardless of the analyser results. These are:
    • Samples from children
    • Pregnant women
    • Urology and nephrology patients
    • Oncology/haematology patients
    • Critical care patients
    • Patients with clinical details of suspected prostatitis or epididymo-orchitis
  • Urgent microscopy requests may be requested on children according to current NICE guidelines.
  • Patients with ongoing urinary symptoms recently screened as negative can have repeat samples sent specifically requesting culture.
  • Investigations for casts, cysteinuria and fastidious organisms are not performed routinely and must be specially requested. Prostatic massage samples can be processed on special request.
  • Antibiotic guidelines for the treatment of UTI  (accessible to Trust users only)


Sample requirements

30mL urine bottle with preservative

Bottles should be filled to the red line

30mL sterile universals without preservative are accepted

Collection of Mid-Stream Sample of Urine (accessible to Trust users only)

30 mL sterile urine container with boric acid preservative

Required information

  • Relevant clinical details
  • Current or recent antibiotic therapy
  • Antibiotic allergies
  • Pregnancy status
  • Suspected prostatitis or epididymo-orchitis


Samples in 30 mL urine bottles with preservative may be stored at room temperature for up to 24 hours. If transport is delayed beyond that samples should be refrigerated.

Samples in plain sterile universals must be transported without delay. Refrigerate samples if transport is delayed.

Turnaround time

Negative: 1 - 3 days

Positive: 2 - 4 days

Multiply resistant organism require additional testing and may take longer 

Page last reviewed: 06/08/2014