α-HBDH

What is α-HBDH?

α-Hydroxybutyrate dehydrogenase (α-HBDH) is a test that primarily measures the activity of LDH-1 and LDH-2 isoenzymes of lactate dehydrogenase.

• LDH exists as 5 isoenzymes (LDH1–LDH5)

• LDH1 & LDH2 are abundant in:

  • ❤️ Heart muscle

  • 🩸 Red blood cells

  • 🧠 Kidneys

α-HBDH activity mainly reflects cardiac and RBC-related LDH activity.

❤️ 1️⃣ Myocardial Infarction (MI)

Before troponins were available, α-HBDH was used as a marker of MI.

⏱ Time Course in MI

• Rises: 12–24 hours

• Peaks: 48–72 hours

• Returns to normal: 7–10 days

🩸 2️⃣ Hemolytic Anemia

Since RBCs contain high LDH1:

• α-HBDH is elevated in:

  • Hemolytic anemia

  • Transfusion reactions

  • Ineffective erythropoiesis

It helps assess degree of hemolysis.

🩺 3️⃣ Other Conditions with Elevated α-HBDH

• Myocarditis

• Renal infarction

• Megaloblastic anemia

• Severe tissue necrosis

📊 Clinical Utility Today

• Rarely used now for MI

• May be useful where troponin testing is unavailable

• Can help evaluate hemolytic disorders