Enzymes, Cardiac Markers, Hepatic Tests

1
Enzymes, Cardiac Markers, Hepatic Tests

• clinically useful enzymes tissue sources
• preanalytical variables affecting enzyme
  activities
• isoenzymes
• myocardial markers and diagnosis of myocardial
  injury
• hepatic function, choice of tests, interpretation
  of results

2
Clinically Useful Enzymes

• LDH heart, liver, muscle, RBC, neural
  tissue, leukocytes, tumor cells
• AST liver, heart, muscle
• ALT liver
• CK muscle, heart, neural tissue
• ALP liver, bone, intestine, placenta
• GGT liver, pancreas, kidney

3
Preanalytical Variables

• IN THE PATIENT - age, sex, food, exercise,
  trauma
• IN THE SAMPLE
• Hemolysis -inc in Total LDH LDH 1/II
• EDTA inhibition of ALP

4
(No Transcript)
5
CK Isoenzymes

• Dimer M B monomers
• CK- 1 BB neural mesenchymal tissue
• CK- 2 MB muscle (lt1) heart (lt40)
• CK- 3 MM heart (60 - 80) muscle
  (gt99)

6
(No Transcript)
7
CK Isoforms

• CKMM-3 CKMB-2 (tissue isoforms of CK) after
  tissue release are converted by carboxypeptidases
  in blood to- CKMM-2 CKMM-1, and- CKMB-1

8
(No Transcript)
9
(No Transcript)
10
Detection of Myocardial Injury Major Issues

• THE Acute Coronary Syndrome - stable angina -
  unstable angina - acute myocardial infarction
• Choice of biochemical cardiac marker

11
Acute Coronary Syndrome Risk Stratification

• Chest pain
• ECG ST segment changes
• Troponins
• Other risk factors CRP, fibrinogen, BNP

12
(No Transcript)
13
(No Transcript)
14
Myocardial Markers

• Troponin-I or T
• Myoglobin
• CK- MB
• CK- MB Relative Index
• CK Isoforms

15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
Myocardial Markers
19
(No Transcript)
20
Myocardial MarkersReferences

• Donnelly, R, Millar-Craig, MW Cardiac troponins
  IT upgrade for the heart. Lancet 1998351537-9
• Apple,FS Wu,A Myocardial infarction redefined
  role of cardiac troponin testing. Clin Chem 2001
  47377-8
• Sabatine, MS et al Multimarker approach to risk
  stratification in non-ST elevation ACS.
  Circulation 2002 1051760-3