Alpha-1 Antitrypsin (AAT) Test – Detailed Guide

The Alpha-1 Antitrypsin (AAT) Test measures the level of AAT protein in the blood, which helps protect the lungs and liver from damage. Low AAT levels may indicate Alpha-1 Antitrypsin Deficiency (AATD), a genetic disorder that increases the risk of lung disease (COPD, emphysema) and liver disease (cirrhosis, hepatitis).

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Why is the Alpha-1 Antitrypsin (AAT) Test Done?

✅ Lung Disease Evaluation

• Early-onset emphysema (before age 45)
• Chronic obstructive pulmonary disease (COPD)
• Unexplained shortness of breath
• Lung disease without a history of smoking

✅ Liver Disease Screening

• Unexplained liver disease (cirrhosis, hepatitis)
• Neonatal jaundice (yellowing of skin in infants)
• Family history of liver disease

✅ Genetic Testing for Alpha-1 Antitrypsin Deficiency (AATD)

• If family history of AATD or related lung/liver diseases
• To check for abnormal AAT genes (Pi-typing or genetic mutation analysis)

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Test Procedure

🩸 Blood Sample Collection:

• A small blood sample is drawn from a vein in the arm
• No fasting required

📅 Results Time:

• Usually available in 3–7 days

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Normal Alpha-1 Antitrypsin Levels

🔹 Values may vary based on laboratory reference ranges.

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What Do Abnormal AAT Levels Mean?

🔴 Low AAT Levels May Indicate:

• Alpha-1 Antitrypsin Deficiency (AATD) – Genetic disorder affecting lungs and liver
• Emphysema or COPD (especially in non-smokers)
• Liver disease (cirrhosis, hepatitis, neonatal jaundice)
• Nephrotic syndrome (Kidney disorder leading to protein loss)

🟢 High AAT Levels May Indicate:

• Acute infections, inflammation, or injury
• Chronic diseases (Rheumatoid arthritis, Crohn’s disease, ulcerative colitis)
• Certain cancers (Liver or lung cancer, lymphoma)

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Next Steps If AAT Is Abnormal?

🔬 Further Tests May Be Needed:

• AAT Phenotyping (Pi-typing) – Identifies genetic variants of AAT
• AAT Genetic Test (Mutation Analysis) – Confirms AAT deficiency inheritance
• Liver Function Tests (LFTs) – Checks for liver damage
• Pulmonary Function Tests (PFTs) – Assesses lung function in suspected AATD cases

✅ Management & Treatment:

• For Lung Disease: Avoid smoking, use bronchodilators, oxygen therapy, or AAT replacement therapy
• For Liver Disease: Regular monitoring, avoiding alcohol, liver transplant in severe cases