Lactate Dehydrogenase:
pathophysiologic marker
Sara Pape-Salmon NP(F)
Mental Health and Addictions
Service, VIHA
What is Lactate Dehydrogenase?
Lactate Dehydrogenase (LDH)
 Intracellular enzyme
 Found in the cells of many body tissues:
 Heart, liver, RBC, kidneys, skeletal muscle
brain, and lungs.
 When these cells become injured, they lyse
& LDH enters the blood stream.
LDH Fractions:
LDH - although nearly ubiquitous body
distribution, five separate fractions exist:
 LDH 1
 LDH 2
 LDH 3
 LDH 4
 LDH 5
LDH Tissue Distribution:
• LDH - Total LDH
• LDH 1 - Found in HEART predominantly
• LDH 2 - RETICULOENDOTHELIAL system
• LDH 3 - LUNGS (predominantly)
• LDH 4 - KIDNEY, PLACENTA, PANCREAS
• LDH 5 - mainly LIVER and STRIATED
MUSCLE
LDH & certain diseases:
 LDH 1 - indicates MI (> LDH 2). Testicular tumors.
 LDH 2 & 3 - Pulmonary disease: CHF, embolism,
infarct, pneumonia, lymphoma & other
reticuloendothelial tumors. AIDS - histoplasmosis.
 LDH 4 - Pancreatitis, kidney disease
 LDH 5 - liver disease (hepatitis, cirrhosis, neoplasm)
ischemic bowel disease, striated muscle disease
(muscular dystrophy, strenuous exercise)
Should we be ordering LDH?
 Although certain LDH patterns are classic for
certain diseases, it is non-specific.
 There are other tests/enzymes that are more
specific
 Can it be an important adjunct - yes…?
 e.g. declining transaminases in context of liver
disease
 e.g. differentiating angina from heart attack
 e.g. differentiate hepatic disease from benign
condition (Gilbert’s disease vs. hemolytic disease)