Can you interpret the lab results: creatine kinase (CK) 5.2 U/L (reference 3.5–9.1), creatine kinase‑MB (CK‑H) 6.7 U/L (reference 4.3–8.3), creatinine (CRTH) 68.4 µmol/L (reference 52–70), and CFFH 36.8 (reference 15–32)?

TEG Lab Results Interpretation

These results show normal CK and creatinine levels, but the CK-MB is mildly elevated and CFFH is significantly elevated above the reference range, which requires clinical correlation with symptoms to determine if this represents acute myocardial injury or another cause of cardiac biomarker elevation.

Individual Parameter Analysis

Creatine Kinase (CK): 5.2 U/L (Reference: 3.5-9.1)

• Normal and unremarkable
• This extremely low CK value essentially rules out significant skeletal muscle damage, rhabdomyolysis, or extensive myocardial necrosis 1, 2
• CK levels >1000 U/L indicate rhabdomyolysis, and levels >3000-5000 U/L are considered pathological with increased risk of acute kidney injury 3, 2
• Your value is well within normal limits

CK-MB (CK-H): 6.7 U/L (Reference: 4.3-8.3)

• Within normal range but in the upper half
• Cardiac troponin is the preferred biomarker for myocardial infarction diagnosis; CK-MB is an acceptable alternative only when troponin is unavailable 1
• Critical caveat: The CK-MB/CK ratio here is 1.29 (129%), which is markedly abnormal. In myocardial infarction, the CK-MB/CK ratio should be approximately 0.1 (10% of total CK) until peak values are reached 4
• This extremely high ratio (>100%) suggests either:
  • Laboratory error or specimen handling issue
  • Macro-CK (immunoglobulin-bound CK causing falsely elevated CK-MB)
  • The units may be different between CK and CK-MB measurements

Creatinine (CRTH): 68.4 µmol/L (Reference: 52-70)

• Normal, at the upper limit of normal
• Indicates preserved renal function
• Rules out acute kidney injury that might accompany severe rhabdomyolysis 2

CFFH: 36.8 (Reference: 15-32)

• Elevated above reference range by approximately 15%
• Without knowing what CFFH specifically measures (this is not a standard laboratory abbreviation), interpretation is limited
• If this represents a cardiac-specific marker, the elevation warrants investigation

Clinical Decision Algorithm

Step 1: Assess for Acute Coronary Syndrome

• If patient has chest pain, dyspnea, or symptoms suggestive of acute coronary syndrome:
  • Obtain cardiac troponin immediately (preferred biomarker) 1, 5
  • Perform ECG
  • Repeat troponin at 6-9 hours if initial is negative 1
  • The CK-MB value alone is insufficient for diagnosis given the abnormal CK-MB/CK ratio

Step 2: If No Cardiac Symptoms

• Investigate the abnormal CK-MB/CK ratio:
  • Repeat both CK and CK-MB measurements to rule out laboratory error
  • Consider macro-CK testing if ratio remains abnormal
  • Verify units of measurement are consistent

Step 3: Address Elevated CFFH

• Determine what CFFH specifically measures
• If cardiac-related, correlate with clinical presentation
• If persistently elevated without clear cause, consider cardiology consultation

Key Pitfalls to Avoid

1. Do not diagnose myocardial infarction based on CK-MB alone - Troponin exceeding the 99th percentile is required for MI diagnosis 1, 5

2. Do not ignore the impossible CK-MB/CK ratio - A ratio >100% is physiologically implausible and suggests measurement error 4

3. Do not assume normal CK rules out all cardiac pathology - Small infarcts or early presentation may show normal CK with elevated troponin 1

4. Do not delay treatment if ECG shows ST-elevation - Treatment should not await biomarker results in STEMI 1

Immediate Recommendations

• If symptomatic: Obtain cardiac troponin and ECG immediately
• If asymptomatic: Repeat CK and CK-MB measurements with attention to proper specimen handling and unit verification
• Monitor: The elevated CFFH requires clarification of what this parameter measures and clinical correlation
• Renal function: Currently preserved; no intervention needed

The preserved renal function with normal CK effectively rules out rhabdomyolysis-related complications 2, 6. The key concern is determining whether the CK-MB elevation represents true myocardial injury (requiring troponin confirmation) or a laboratory artifact (suggested by the impossible CK-MB/CK ratio).