Persistently elevated CKMB and negative troponin T in a patient at ischaemic risk with chest pain

Area of Science:

• Clinical Biochemistry
• Laboratory Medicine
• Diagnostic Assays

Background:

• Analytical interference in laboratory testing is a significant clinical challenge.
• Unrecognized interferences can lead to patient misdiagnosis and inappropriate management.
• Creatine kinase MB (CKMB) activity assays are crucial for diagnosing myocardial infarction.

Observation:

• A patient presented with chest pain and ischemic risk factors.
• Incongruent biochemical results were observed during laboratory analysis.
• The presence of macro-creatine kinase (macro-CK) was identified as the cause.

Findings:

• Macro-CK, an in vivo complex of CK isoforms, interfered with the CKMB activity assay.
• This interference led to inaccurate CKMB measurements.
• The specific mechanism of interference was identified in this case.

Implications:

• Accurate laboratory diagnostics are essential for effective patient care.
• Awareness of macro-CK interference is critical for clinical laboratory scientists and physicians.
• This case underscores the need for robust analytical interference detection protocols in clinical laboratories.