CK Isoenzymes (CKISO, CK Isoforms)
Human enzyme creatine kinase is composed of two subunits, M (muscle) & B (brain) arranged into dimers giving rise to three possible isoenzymes: MM, MB & BB.
The primary use of CK isoenzyme analysis is the identification of Macro CK Type 1 (a CK–immunoglobulin complex) or Macro CK Type 2 (mitochondrial CK) in individuals with a persistently raised total CK without obvious heart or muscle disease.
Although CKMB > 5 % may be indicative of acute myocardial infarction, Troponin is a sensitive and specific marker of cardiac damage and CK isoenzyme analysis is now not routinely indicated for this purpose.
CK Isoenzymes is a semi-qualitative test with interpretation provided. Analysis identifies which isoenzyme(s) are responsible for the elevation in total CK as well as detection of type 1 or type 2 macro-CKs.
The relative contribution of each isoenzyme present is provided as part of the report.
Sample can be sent by first class post.
Please include the Total CK result on the request if available.
Specimens containing inhibitors of CK activity e.g. heparin, EDTA, citrate, fluoride or iodoacetate are unsuitable.
Record last updated
August 15, 2025
Sample Container
6ml Plain Vacutainers (Red top)
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Test Results
Yes, we have a Pathology User Guide
Yes. Please email your request to Imperial.nwlpcustomerservice@nhs.net
Results are communicated to clinical staff and are normally not communicated direct to patients either on telephone requests or in written report. If you need to contact us please click here to view the contact details page
Please contact the Customer Service Team Monday to Friday from 8:30am – 6:00pm on 0203 313 5353. Alternatively, see the Pathology User Guide for how to contact the relevant department. If advice is not urgent you can also email your query to Imperial.nwlpcustomerservice@nhs.net
Additional tests may be added by discussion with the relevant laboratory. The time limit for adding additional tests to a sample already received in the laboratory will depend on the type of sample and the department it was sent to.
Information on the repertoire of tests performed by pathology, including reference ranges, turnaround times and specimen requirements, can be found in the test directory.
Different tests have different sample stability requirements. If a comment on results indicates that the sample was delayed, the links below will indicate which tests may have been affected. This information is for serum or plasma samples.
For some tests, the impact of delay is consistent and these are marked with an arrow:
↑ indicates tests where delayed centrifugation results in falsely elevated results and the true level is likely lower than that reported.
↓ indicates tests where delayed centrifugation results in falsely lowered results and the true level is likely higher than that reported.
If there is no arrow, the true level may be lower or higher than reported.
Please interpret results with caution and consider the impact of any uncertainty.
The comment on the report will state how delayed the sample was. Please click the relevant link below to see which other tests may have been affected.
| >8h | >12h | >24h | >48h | >72h |
Phlebotomy services are not managed by NWLP. For further information please see:
Imperial College Healthcare Trust Phlebotomy services
Chelsea and Westminster Hospital NHS Foundation Trust Phlebotomy services
NWLP operates UKAS accredited medical laboratories as per the references below. The current scope of accreditation for all NWLP’s laboratories can be found on the UKAS website.
UKAS accredited medical laboratory/medical diagnostic service:
- Clinical Biochemistry No. 8673
- Haematology and Blood Transfusion No. 8674
- Infection & Immunity Sciences (Including Immunology, Virology, Microbiology and Histocompatibility and Immunogenetics ) No. 8659
- Cellular Pathology (Including Histopathology, Cytology and Molecular Pathology) No. 9615
If you require copies of our certificate of accreditation and associated documentation please contact Imperial.nwlpcustomerservice@nhs.net.
UKAS requires the laboratories to be accredited for a particular repertoire/scope (ISO15189), any changes or additions to repertoire require assessment by UKAS (extension to scope).
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Our accreditations
Upholding excellence in diagnostic standards
Our laboratories are accredited by the UK Accreditation Service (UKAS) against the international standard ISO15189:2022. UKAS is the accreditation body for the UK that assesses medical laboratories.
Find out more about our accreditations on the UKAS website.
UKAS website