Understanding your mid-stream urine (MSU) results

A mid-stream urine (MSU) test is usually done to check for an infection in your bladder or kidneys. When collecting the wee (urine), it is important to try to get a clean sample to get an accurate result.

On this page

Terms used in your MSU results

Microscopy 

Microscopy shows what the laboratory sees looking at your wee under a microscope.

Leukocytes (WBC)

Leukocytes are white blood cells (WBC) that your body makes to fight infections.

Erythrocytes (RBC)

Erythrocytes are red blood cells (RBC) that are usually only present in small amounts in your wee.

Epithelial cells

Epithelial cell are skin cells.

Culture

Culture is what the laboratory finds after trying to grow bugs (bacteria or fungi).

Susceptibilities

Susceptibilities show if the bug will be affected by a particular antibiotic.

Your MSU results

Leukocytes (WBC)

  • below 10 is normal
  • 10 to 100 is unlikely to be important
  • above 100 is likely to mean you have an infection.

Erythrocytes (RBC)

  • below 10 is normal
  • 10 to 20 is unlikely to be important
  • above 20 is abnormal.

Epithelial cells

  • below 10 is normal
  • above 10 means the wee sample may be contaminated.

Culture

  • 'no significant growth' means no infection was found
  • 'mixed growth' means no single cause of infection was found
  • growth of one bug, for example 'E. coli, <100 x 106', means the bug is present but may not be causing an infection
  • growth of one bug, for example 'E. coli, >100 x 106', means the bug is likely to be the cause of an infection.

Susceptibilities

  • an antibiotic name with 'S' means the bug will be affected by that antibiotic
  • an antibiotic name with 'R' means the bug will be resistant to that antibiotic.

After you get your MSU results

If your urinary tract infection (UTI) symptoms have improved, you will not need any further tests.

If you keep having symptoms such as pain or you need to have a wee more often than usual, contact your healthcare provider for advice. There may another cause for your symptoms.

If you have leukocytes (WBC) in your urine but no growth from the urine culture, you may need to be checked for a sexually transmitted infection (STI).

Sexually transmitted infections (STIs) (internal link)

If you continue to have blood in your wee (haematuria) after your infection has gone away, contact your healthcare provider as you may need further tests.

Blood in the urine (haematuria) (internal link)

If you have any questions about your MSU results, talk with your healthcare provider.