Serum Albumin Test: Purpose, Procedure, and Normal Values
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Why is this test performed?
This test is evaluated in different conditions and diseases such as nephrotic syndrome, liver diseases, kidney diseases, in a patient suspected of malnutrition, and patients severe burn. See also: Procedures for the collection of blood for hemotological investigations.
Collection of sample
About 3 to 5 ml of blood is collected in a plain test tube and blood is allowed to clot to get clear serum. The blood sample is centrifuged for 5 to 10 minutes and the serum is separated for the test. The patient's serum is may be stored at 4° C which may be stable for 72 hours.
- Fasting blood sample is preferred.
- Specimen with lipemia or hemolysis should be avoided.
- This is the richest protein in the blood.
- Plasma proteins are separated into three major groups:
- The most common method is electrophoresis. It forms 5 bands named as:
(b) α1 fraction
(c) α2 fraction
(d) β fraction
(e) γ fraction
- Total protein is made up of 40 to 60% of albumin.
(a) Because of its low molecular size and high concentration in blood, it is found in urine, cerebrospinal fluid (CSF), interstitial fluid, amniotic fluid, and most of the extravascular fluids.
(b) Due to its negative charge at normal pH, it is highly water soluble.
(c) The half-life of albumin is about 15 to 19 days.
(d) It is extremely sensitive to liver damage.
(e) It helps to maintain the osmotic pressure in the blood vessels, without which the fluid will leak out.
(f) It synthesized in the liver, that is why it reflects the functions of liver and kidney.
(g) Albumin binds calcium, bilirubin, free fatty acids, and a number of drugs.
(h) Low level of albumin causes Edema.
(i) In acute or chronic liver diseases, malignancy, Amyloidosis, and malnutrition decreased synthesis in the liver is seen.
(j) The role of albumin in transporting calcium, bilirubin, bile acids, metal ions, and drugs will be the variation in its concentration.
(k) The presence of albumin in the urine represents kidney diseases.
(l) Dehydration causes an increase in the level of albumin (Hyperalbuminemia).
(m) The albumin performs a role of carrier protein for calcium, bilirubin, progesterone, and drugs.
(n) Albumin provides nutrition to the tissues and binds various molecules like vitamin, hormones, and drugs.
It is defined as a condition in which the level of albumin in blood/serum is lower than the normal values.
It is defined as a condition in which the level of albumin in blood/serum is higher than the normal values.
- 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 (Spot Urine) 1 to 14 mg/mL
- 24-hour Urine 15 to 45 mg /24 hours
- Newborn 2.8 to 4.8 g/dl