🧪 Albumin Serum for Laboratory Investigations

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📌 Introduction

Serum albumin is one of the most important proteins measured in clinical laboratory investigations. It plays a crucial role in maintaining oncotic pressure and transporting various substances in the blood. Measurement of serum albumin is a routine part of liver function tests (LFTs), renal panels, and general health assessments.

🧬 What is Albumin?

Albumin is a protein synthesized in the liver and released into the bloodstream. It constitutes about 55–60% of total plasma protein.

🔹 Main Functions:

• Maintains colloid osmotic (oncotic) pressure

• Transports hormones, fatty acids, bilirubin, calcium, and drugs

• Acts as a buffer in acid-base balance

• Serves as a nutritional marker

🧪 Specimen Requirements for Albumin Testing

1️⃣ Sample Type

• Serum (preferred)

• Plasma (heparinized)

2️⃣ Collection Method

• Collect venous blood in a plain (red-top) tube

• Allow blood to clot (15–30 minutes)

• Centrifuge to separate serum

3️⃣ Storage Conditions

• Room temperature: 8 hours

• Refrigerated (2–8°C): 48 hours

• Frozen (-20°C): Longer storage

⚙️ Methods of Albumin Estimation

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🔬 1. Bromocresol Green (BCG) Method

• Most commonly used method

• Albumin binds with BCG dye

• Color intensity measured spectrophotometrically

🔬 2. Bromocresol Purple (BCP) Method

• More specific than BCG

• Less interference from globulins

🔬 3. Serum Protein Electrophoresis

• Separates proteins by charge

• Identifies albumin fraction and other protein abnormalities

📊 Normal Reference Range

⚠️ Reference ranges may vary slightly depending on laboratory standards.

📉 Causes of Low Serum Albumin (Hypoalbuminemia)

• Liver disease (e.g., cirrhosis, hepatitis)

• Nephrotic syndrome

• Malnutrition

• Chronic inflammation

• Burns

• Protein-losing enteropathy

Clinical Signs:

• Edema

• Ascites

• Fatigue

📈 Causes of High Serum Albumin (Hyperalbuminemia)

• Dehydration

• Severe diarrhea

• Excessive diuretic use

True hyperalbuminemia is rare; most cases are due to hemoconcentration.

🏥 Clinical Significance

Serum albumin is commonly assessed in:

• Liver function tests (LFT)

• Renal profile

• Nutritional assessment

• Critically ill patients

• Chronic disease monitoring

Low albumin levels are associated with poor prognosis in hospitalized and ICU patients.

🧾 Interpretation Tips for Laboratory Professionals

• Always correlate with total protein levels

• Consider A/G ratio (Albumin/Globulin ratio)

• Check for hemolysis or sample dilution errors

• Interpret alongside clinical findings

🔎 Quality Control in Albumin Testing

• Run normal and abnormal control sera daily

• Calibrate analyzer regularly

• Monitor reagent stability

• Avoid hemolyzed or lipemic samples

📚 Conclusion

Serum albumin estimation is a fundamental laboratory investigation with significant diagnostic and prognostic value. Proper sample collection, accurate methodology, and careful interpretation are essential to ensure reliable results.