Blood tests


Blood test services at Charing Cross and Hammersmith hospitals are a walk-in service as requested by GPs or a clinical staff member. St Mary's Hospital offers a walk-in service for blood tests requested by Trust clinical staff — St Mary's does not accept blood test requests from GPs.

A blood test is when a sample of blood is taken to be tested in a laboratory. Blood tests have a wide range of uses and are one of the most common types of medical test. For example, a blood test can be used to:

  • assess your general state of health
  • confirm the presence of a bacterial or viral infection
  • see how well certain organs, such as the liver and kidneys, are functioning
  • screen for certain genetic conditions

Blood testing walk-in services

Walk-in blood testing services are available Monday through Friday at the main outpatients departments at Charing Cross, Hammersmith and St Mary's hospitals. 

Charing Cross Hospital

Monday through Friday

08.00 to 18.45

Hammersmith Hospital

Monday through Friday

08.00 to 18.45

St Mary's Hospital

Monday through Friday

09.00 to 17.00

Please note:

  • The blood testing service at St Mary's Hospital does not accept referrals from GPs. All patients referred by their GP should contact their own GP practice to find the right place to have their blood test done. Please see our clinics page for more information. 
  • The blood testing service at Charing Cross Hospital is exceptionally busy on Mondays and Tuesdays. Please consider using the service on Wednesday, Thursday or Friday if possible.

Additional information

For a glucose tolerance test (GTT) you need to book an appointment in advance by calling 020 3311 1101.