Skip to content



Blood tests have a wide range of uses and are one of the most common and routinely performed types of medical test carried out on patients. Blood tests can be used to assess a patient’s general state of health, test for viral infection, assess the function of certain organs (such as the liver and kidneys), measure oxygen and carbon dioxide levels, and are used for genetic testing.

Diagnostic blood tests must only be coded when the patient is admitted solely for the purpose of the diagnostic blood test, using the following OPCS-4 codes:

U32.1 Human Immunodeficiency Virus blood test

X36.3 Venous sampling

X36.8 Other specified blood withdrawal

X36.9 Unspecified blood withdrawal

OPCS-4 codes U32.1 Human Immunodeficiency Virus blood test (a blood test performed to detect HIV antibodies that are produced in response to infection) and X36.3 Venous sampling, (in which a sample of blood is taken from a certain vein, such as jugular or portal veins, and checked for specific substances released by nearby organs and tissues) must only be assigned when these tests are explicitly documented in the patients medical record or when the clinician has confirmed that these tests have been performed. For example, if the patient medical record states ‘HIV blood test’ or ‘venous sampling’.

OPCS-4 code X36.8 Other specified blood withdrawal, is assigned when another specified type of blood test, which is not a Human Immunodeficiency Virus blood test or Venous sampling, has been performed.

If the type of diagnostic blood test is not specified, then OPCS-4 code X36.9 Unspecified blood withdrawal must be assigned.

Date published: 03/2011 (Volume 7 Issue 9)

Coding Clinic, NHS Classifications Service


Tags: ,

%d bloggers like this: