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Urine samples

Sample collection

A mid-stream urine (MSU) sample is necessary for aculture so it is important to ensure that the sample is collected aseptically. The procedure for collecting a clean mid-stream includes the following steps:  

  • Thoroughly wash hands
  • Using soap clean the penis in males, and females should wash the external genitalia, holding the labia apart.
  • Repeat this procedure three times.
  • Do not collect the initial stream of urine since it may be contaminated with skin and urethral bacteria and lead to an inconclusive result
  • Midway through urination, collect a sample of urine in a sterile universal
  • Tightly cap the container and wash your hands thoroughly.
  • Ensure the patient’s name is clearly written on the container
  • The sample should be taken taken to the laboratory as quickly as possible to prevent the further growth of organisms.

Uncontaminated specimens can also be obtained from catheterised patients following the same hygienic procedures for the end of the catheter.

Bag urines are only excepted on Neonates, please do not collect bag urines on adult patients..

Suprapubic Aspirates and Nephrostomy Urines must be labelled as the relevant sample type.  Collection of these samples types must be by trained staff only.

Please click here for NHS urine sample collection guidelines

How is the sample processed?

Each urine sample is processed microscopically using an automated machine. Depending on the clinical details and microscopic results the urine may then be cultured onto Chromogenic agar and incubated overnight.

All urines that are considered negative by microscopy will not receive a culture and the result will be authorised immediately.

The table below contains the clinical decision values behind what urines will be cultured.  The top 4 highlighted sections will all receive a culture regardless of the microscopy result. It is therefore paramount that this type of information is provided on the request form. 

Clinical Details

AN or Renal Transplant


Ward 302 ,303 and 314



Specimen Type

UN (Nephrostomy urine) or USP (Supra pubic aspirate urine)


If Yeast or Trichomonas

Polymorph Count

PC >7000





Small Particles



All microscopy positive urines will be cultured over night.  

(Modified Last By: AOM 16.7.16)