- It is done on the serum of the patient.
- How to get good serum: Take 3 to 5 ml of blood in the disposable syringe or in vacutainer. Keep the syringe for 15 to 30 minutes at 37 °C and then centrifuge for 2 to 4 minutes to get clear serum.
- The random sample can be taken.
- Use a freshly prepared serum or store at 4 °C which may be stable more than 72 hours.
- Fasting sample is preferred.
- Specimen with lipemia or hemolysis should be avoided.
- Avoid prolonged tourniquet.
- Take into account physical exercise and fever where there is increased filtration.
- This test is needed:
- in liver diseases.
- kidneys diseases and nephrotic syndrome patient.
- In patients with severe burn.
- As a part of other tests.
- In a patient suspected of malnutrition.
- This is the most abundant protein in the blood.
- Plasma proteins are separated into three major groups:
- The most common method is electrophoresis. This forms 5 bands named as:
- α1 fraction.
- α2 fraction.
- β fraction.
- γ fraction.
- 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.
- Albumin is coded by a gene on the long arm of chromosome 4.
- Albumin makes 40 to 60% of the total proteins.
- 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.
- It is highly water soluble due to its negative charge at normal pH.
- Albumin half-life is 15 to 19 days.
- It is needed to maintain the osmotic pressure in the blood vessels without which fluids will leak out.
- Primary function is the maintenance of Colloidal osmotic pressure maintenance of vascular and extravascular spaces with continuous equilibrium.
- It is extremely sensitive to liver damage.
- This protein is synthesized primarily from the hepatocytes of the liver and reflects the function of the liver, kidney, or malnutrition.
- The synthetic reserve of the liver is enormous, e.g in nephrotic syndrome may be 300% of the normal rate.
- The synthetic rate is controlled by colloid osmotic pressure and secondarily by the protein intake.
- The synthesis is decreased by the inflammatory cytokines of
- Albumin binds bilirubin, free fatty acids, calcium, and a number of drugs.
- Low albumin results in Edema.
- Decreased synthesis in the liver is seen in acute or chronic liver diseases, Amyloidosis, malnutrition, and malignancy.
- Its role in transporting bilirubin, bile acids, metal ions, and drugs will be markedly affected by variation in its concentration.
- The presence of albumin in the urine indicates kidney disease.
- Dehydration leads to an increase in albumin level (Hyperalbuminemia).
- Albumin functions:
- 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.
- Albumin prevents edema.
- Albumin provides nutrition to the tissues and binds various molecules like salicylates, fatty acids, magnesium ions, cortisol, hormones, vitamins, and drugs.
- Albumin acts as a carrier protein for bilirubin, calcium, progesterone, and drugs.
- Hypoalbuminemia when the albumin level is lower than the normal.
- Hyperalbuminemia when the albumin level is higher than the normal level.
- Normal range = 3.4 to 5.5 g/dl (35 to 55 g/L).
- Cerebrospinal fluids = 15 to 45 mg/dl
- 1 to 14 mg/dL
- 15 to 45 mg /24 hours
- Newborn = 2.8 to 4.8 g/dl
Albumin level decreases in:
- Acute and chronic inflammations:
- The cause is hemodilution, loss into extravascular space, increased consumption by the cells and decreased synthesis.
- like Rheumatoid arthritis, granulomatous process, most bacterial infections, vasculitis, ulcerative bowel disease, and certain parasitic infestation.
- Due to decreased synthesis by the liver:
- This may be due to the increased amount of immunoglobulins, loss of albumin into the extravascular space.
- This may be also due to the decreased synthesis because of toxins or alcohol.
- The liver can compensate for the synthesis of albumin approximately up to 95% of the loss of liver function.
- In acute and chronic liver diseases, Amyloidosis, Malignancies, Congestive heart disease, and constrictive pericarditis.
- Urinary loss:
- 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.
- Normal urine contains 20 mg of albumin per gram of creatinine.
- Excretion above this level is seen in:
- Increased glomerular filtration.
- Tubular damage.
- Or a combination of the above factors.
- Examples are:
- In Nephrotic syndrome.
- Thermal burns.
- Trauma and crush injuries.
- Transudation and exudation from any hollow organs.
- Increased loss via body fluids.
- Increased catabolism:
- leads to decrease albumins like fever, antimetabolites, thyrotoxicosis, and certain malignancies.
- A gastrointestinal loss:
- With the inflammatory disease of GIT.
- Chronic protein-losing enteropathy.
- Increased blood volume (hypervolemia):
- This leads to a decrease in albumins like exogenous estrogen therapy, Myeloma, and congestive heart failure.
- Serum level decreases in pregnant ladies.
- The person on a low protein diet.
- It decreases:
- After weight loss surgery.
- Whipple disease.
- Crohn's disease.
- Analbuminemia is a rare genetic deficiency where plasma albumin level is <0.5 g/L. Major clinical manifestations are related to abnormal lipid transport.
- Summary of decreased albumin:
- Hepatic diseases.
- Urinary loss.
- Gastrointestinal loss.
- Edema and ascites.
- Protein malnutrition.
Albumin level increases in:
- Naturally, there is no reason for the increase in the albumin level.
- Dehydration or any other cause leading to a decrease in the plasma volume causes an increase in the level.
- High protein diet.
- When the tourniquet is applied for a long time.
Tabulated causes of Hyperalbuminemia and Hypoalbuminemia:
|High protein diet
||False value due to prolonged tourniquet
|Decreased protein intake
Possible References Used
Back to tests