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Sample

Precaution

  1. Fasting sample is preferred.
  2. Specimen with lipemia or hemolysis should be avoided.
  3. Avoid prolonged tourniquet.
  4. Take into account physical exercise and fever where there is increased filtration.

Indications

  1. This test is needed:
    1. in liver diseases.
    2. kidneys diseases and nephrotic syndrome patient.
    3. In patients with severe burn.
    4. As a part of other tests.
    5. In a patient suspected of malnutrition.

Pathophysiology

    1. This is the most abundant protein in the blood.
    2. Plasma proteins are separated into three major groups:
      1. Fibrinogen.
      2. Globulins.
      3. Albumin
    3. The most common method is electrophoresis. This forms 5 bands named as:
      1. Albumin.
      2. α1 fraction.
      3. α2 fraction.
      4. β fraction.
      5. γ fraction.

     

    1. Albumin Concentration at birth is 39 g/L, then it decreases to 24 g/L at 9 months, again rises to 35 to 55 g/L at adult age and after the age of 60 years is 38.3 g/L.     
      1. Albumin is coded by a gene on the long arm of chromosome 4.           

    1. Albumin makes 40 to 60% of the total proteins.
      1. Because of its high concentration in the plasma and small molecular size, it is found in most of the extravascular fluids, CSF, amniotic fluid, urine, and interstitial fluid.
      2. It is highly water soluble due to its negative charge at normal pH.
      3. Albumin half-life is 15 to 19 days.

    1. It is needed to maintain the osmotic pressure in the blood vessels without which fluids will leak out.
      1. Primary function is the maintenance of Colloidal osmotic pressure maintenance of vascular and extravascular spaces with continuous equilibrium.
    2. It is extremely sensitive to liver damage.
    3. This protein is synthesized primarily from the hepatocytes of the liver and reflects the function of the liver, kidney, or malnutrition.
      1. The synthetic reserve of the liver is enormous, e.g in nephrotic syndrome may be 300% of the normal rate.
      2. The synthetic rate is controlled by colloid osmotic pressure and secondarily by the protein intake.
      3. The synthesis is decreased by the inflammatory cytokines of 
    4. Albumin binds bilirubin, free fatty acids, calcium, and a number of drugs.
    5. Low albumin results in Edema.
      1. Decreased synthesis in the liver is seen in acute or chronic liver diseases, Amyloidosis, malnutrition, and malignancy.
      2. Its role in transporting bilirubin, bile acids, metal ions, and drugs will be markedly affected by variation in its concentration.

    1. The presence of albumin in the urine indicates kidney disease.
    2. Dehydration leads to an increase in albumin level (Hyperalbuminemia).
    3. Albumin functions:
      1. One most important function is to maintain the colloid osmotic pressure of the intravascular fluid. Because of the high concentration, it is responsible for 80% of this pressure.
      2. Albumin prevents edema.
      3. Albumin provides nutrition to the tissues and binds various molecules like salicylates, fatty acids, magnesium ions, cortisol,  hormones, vitamins, and drugs.
      4. Albumin acts as a carrier protein for bilirubin, calcium, progesterone, and drugs. 

 

 

Normal

      • Normal range               =  3.4 to 5.5 g/dl (35 to 55 g/L).
        • Male                     = 4.2 to 5.5 g /dl
        • Female                  = 3.7 to 5.3 g/dl
      • Cerebrospinal fluids    = 15 to 45 mg/dl
      • Urine                               
        • 1 to 14 mg/dL
        • 15 to 45 mg /24 hours
      • Newborn                        = 2.8 to 4.8 g/dl

Albumin level decreases in:

    1. Acute and chronic inflammations: 
      1. The cause is hemodilution, loss into extravascular space, increased consumption by the cells and decreased synthesis.
        1. like Rheumatoid arthritis, granulomatous process, most bacterial infections, vasculitis, ulcerative bowel disease, and certain parasitic infestation.
    2. Due to decreased synthesis by the liver:
      1. This may be due to the increased amount of immunoglobulins, loss of albumin into the extravascular space.
      2. This may be also due to the decreased synthesis because of toxins or alcohol.
      3. The liver can compensate for the synthesis of albumin approximately up to 95% of the loss of liver function.  
        1. In acute and chronic liver diseases, Amyloidosis, Malignancies, Congestive heart disease, and constrictive pericarditis.
    3. Urinary loss:
      1. As albumin is relatively small and globular, a significant amount is filtered into the glomerular urine. Then the majority is reabsorbed by the proximal tubular cells.
      2. Normal urine contains 20 mg of albumin per gram of creatinine.
        1. Excretion above this level is seen in:
          1. Increased glomerular filtration.
          2. Tubular damage.
          3. Hematuria.
          4. Or a combination of the above factors.
      3. Examples are:
        1. In  Nephrotic syndrome.
        2. Thermal burns.
        3. Trauma and crush injuries.
        4. Transudation and exudation from any hollow organs.
        5. Increased loss via body fluids.

    1. Increased catabolism:
      1. leads to decrease albumins like fever, antimetabolites, thyrotoxicosis, and certain malignancies.
    2. A gastrointestinal loss:
      1. With the inflammatory disease of GIT. 
      2. Chronic protein-losing enteropathy.
    3. Increased blood volume (hypervolemia):
      1. This leads to a decrease in albumins like exogenous estrogen therapy, Myeloma, and congestive heart failure.
      2. Serum level decreases in pregnant ladies.
      3. The person on a low protein diet.
    4. It decreases:
      1. After weight loss surgery.
      2. Whipple disease.
      3. Sprue.
      4. Crohn's disease.
    5. Analbuminemia is a rare genetic deficiency where plasma albumin level is <0.5 g/L. Major clinical manifestations are related to abnormal lipid transport.
    6. Summary of decreased albumin:
      1. Inflammations.
      2. Hepatic diseases.
      3. Urinary loss.
      4. Gastrointestinal loss.
      5. Edema and ascites.
      6. Protein malnutrition.

 Albumin level increases in:

      1. Naturally, there is no reason for the increase in the albumin level.
      2. Dehydration or any other cause leading to a decrease in the plasma volume causes an increase in the level.
      3. High protein diet.
      4. When the tourniquet is applied for a long time. 

Tabulated causes of Hyperalbuminemia and Hypoalbuminemia:

Hypoalbuminemia Hyperalbuminemia
Nephrotic syndrome Dehydration

Burns

High protein diet
Blood loss False value due to prolonged tourniquet
Malignancies  
Inflammatory process  
Liver diseases  
Decreased protein intake  
Ascites  

Possible References Used

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