Albumin (Serum & Body Fluid)

Overview

Albumin is the major plasma protein, produced by the liver and present in blood and all body fluids. As described on pages 2–4 of the document, it makes up 50–60% of total body proteins and plays a crucial role in maintaining oncotic pressure, ensuring that fluid stays within blood vessels rather than leaking into tissues. Beyond fluid regulation, it transports vitamins, enzymes, fatty acids, bilirubin, hormones, drugs, and electrolytes, making it vital for multi-system stability.

Page 3 highlights its added functions, including antioxidant activity, detoxification of harmful substances, and several enzymatic roles. It is measurable not only in serum but also in CSF, pleural fluid, ascitic fluid, pericardial fluid, and synovial fluid, making it essential for diagnosing systemic diseases and local body-fluid disorders.

The document also explains the diagnostic importance of these levels in differentiating transudates and exudates in body fluids, especially through SAAG (Serum–Ascites Albumin Gradient), a reliable marker for evaluating ascites (page 11).

Symptoms

Symptoms prompting albumin testing generally relate to low albumin (hypoalbuminemia) because abnormalities in albumin concentration affect fluid balance, tissue perfusion, and immune function.

According to page 10, low levels may present with:

Fluid Retention Symptoms

1. Peripheral edema: swelling of legs, arms, and ankles
2. Ascites: abdominal swelling due to fluid accumulation
3. Pleural effusion: shortness of breath from fluid in the lungs

General Symptoms

1. Fatigue or generalized weakness
2. Weight gain due to fluid retention
3. Dry, wrinkled skin

Immune System Effects

1. Increased susceptibility to infections because low albumin impairs immune function

These symptoms indicate poor protein status, liver dysfunction, kidney disease, or systemic inflammation—conditions that require this evaluation in serum or body fluids.

Causes

The document highlights several physiological and pathological causes for low or high levels of these.

Causes of Low Albumin (Hypoalbuminemia)

(Page 13)

1. Malnutrition: inadequate protein intake prevents albumin synthesis
2. Liver disease (e.g., cirrhosis): the liver cannot produce enough albumin
3. Renal disease: albumin is lost through urine in conditions like nephrotic syndrome
4. Rheumatoid arthritis and chronic inflammation: Inflammatory states reduce albumin synthesis
5. Exposure to hepatotoxins or inflammatory conditions (page 4)
6. Protein-calorie deficiency, as suggested in clinical applications on page 14

Causes of High Albumin (Hyperalbuminemia)

1. Dehydration
2. Skin-related fluid loss, such as burns or dermatitis

Technical Causes Affecting Measurement

1. Excessive hemolysis falsely elevates albumin
2. Color reagent interference due to detergents or dioxane
3. Ampicillin interference in BCG dye-binding
4. BCG binds non-specifically with alpha and beta-globulins at low albumin levels

Risk Factors

Risk factors arise from clinical conditions or treatments that increase the likelihood of abnormal albumin levels.

1. Liver or Kidney Disease

Page 5 lists liver or kidney disease as primary indications for ordering albumin testing.

2. Poor Nutritional Status

Low protein intake directly affects synthesis (pages 4 and 13).

3. Chronic Inflammatory Disorders

Conditions like rheumatoid arthritis or chronic illness reduce albumin due to inflammation (page 13).

4. Conditions Leading to Fluid Imbalance

Heart failure, nephrotic syndrome, and ascites shift fluids, decreasing measured albumin.

5. Medications That Increase Albumin Levels

Page 6 lists anabolic steroids, growth hormone, androgens, and insulin as agents that elevate albumin, requiring temporary discontinuation before testing.

6. Critically Ill Patients

Page 14 notes its importance in critical care for monitoring nutritional and inflammatory status.

7. Body-Fluid Pathologies

Any disorder affecting pleural, ascitic, synovial, or pericardial fluids requires this measurement to differentiate transudate from exudate using SAAG or fluid thresholds (page 11).

Prevention

While albumin abnormalities stem from underlying diseases, the document outlines steps to prevent misdiagnosis, erroneous results, and clinical complications.

1. Proper Sample Collection

1. Collect 3.0 mL of blood in a plain red-capped tube
2. Separate serum promptly before sending to the lab

2. Avoid Interfering Medications Before Testing

Temporarily stop anabolic steroids, androgens, insulin, and growth hormone.

3. Maintain Adequate Nutrition

Since this synthesis depends on protein intake (page 4), balanced nutrition helps stabilize levels.

4. Manage Liver and Kidney Conditions Early

Early intervention prevents severe hypoalbuminemia.

5. Ensure Accurate Testing Methods

Use appropriate assays such as biuret, BCG dye-binding, or immunoassays (page 8) while being aware of limitations (page 15).

6. Correct Interpretation of Body Fluid Results

Use SAAG >1.1 g/L to classify ascites as transudate and <1.1 g/L as exudate (page 11), preventing diagnostic errors.