LDH-4 is the fourth isoenzyme of lactate dehydrogenase, found predominantly in the kidneys, placenta, and pancreas. When these organs are damaged or under stress, LDH-4 is released into the bloodstream and can be detected through isoenzyme analysis.
Elevated LDH-4 alongside other kidney markers may provide additional evidence of renal injury or disease. In obstetrics, LDH-4 from the placenta can contribute to elevated LDH-4 levels in pregnancy. Like other LDH isoenzymes, LDH-4 is most useful when the source of an elevated total LDH is uncertain and tissue-specific differentiation is needed.
FAQs
Which conditions primarily elevate LDH-4?
Kidney injury or disease, pancreatitis, and in pregnancy, placental conditions including pre-eclampsia and HELLP syndrome (haemolysis, elevated liver enzymes, low platelets) can elevate LDH-4.
Is LDH-4 useful for monitoring kidney disease?
Total LDH and isoenzyme analysis can provide supporting evidence of kidney injury, but creatinine, eGFR, and urine markers (urine albumin-to-creatinine ratio) are the primary kidney function tests. LDH-4 provides complementary tissue localisation information.
Can LDH-4 indicate pancreatitis?
Pancreatitis elevates total LDH with a component from LDH-4 and LDH-5. However, amylase and lipase are the primary tests for pancreatitis, being more sensitive and specific than LDH.
What is HELLP syndrome?
HELLP syndrome is a serious pregnancy complication involving haemolysis (elevated LDH), elevated liver enzymes, and low platelet count. It is associated with pre-eclampsia and requires urgent delivery. The LDH elevation in HELLP involves multiple isoenzymes.
