LDH isoenzymes

Alternative names:

lactate dehydrogenase isoenzymes; lactic dehydrogenase isoenzymes; LD1; LD2; LD3; LD4; LD5; LDH1; LDH2; LDH3; LDH4; LDH5

Normal values:

• LDH (total): 115 to 225 IU/L
• LDH-1: 17 to 27 %
• LDH-2: 27 to 37 %
• LDH-3: 18 to 25 %
• LDH-4: 3 to 8 %
• LDH-5: 0 to 5 %

Note: IU/L = international units per liter

What abnormal results mean:

Because LDH is in many tissues in the body, total LDH is not a good indicator of heart disease. Normally, the concentration of LDH-2 is higher than of LDH-1. However, after a heart attack, the concentration of LDH-1 is generally higher than that of LDH-2 (this is called a "flipped" LDH pattern). The serum LDH level rises within 24 to 72 hours after a heart attack, peaks in 3 to 4 days, and returns to normal in about 14 days.

Greater-than-normal LDH isoenzyme levels may be seen in:

• heart attack
• hemolytic anemia
• hypotension
• infectious mononucleosis
• intestinal ischemia (blood deficiency) and infarction (tissue death)
• liver disease (e.g., hepatitis)
• muscle injury
• muscular dystrophy
• pancreatitis
• pulmonary (lung) infarction (tissue death)
• stroke

Additional conditions under which the test may be performed:

• ischemic cardiomyopathy