- The patient's serum is needed for estimation of IgA.
- The random sample can be taken.
- Analyzed a fresh sample or store at 4 °C for less than 72 hours. Stable for 6 months at -20 °C.
- Avoid lipemic or hemolyzed serum.
Factors influencing the result:
- Drugs which will increase the values are:
- Isoniazid (INH).
- Tetanus toxin and toxoid.
- Therapeutic gamma globulins.
- IgA is the second most common Ig and it has two subclasses:
- IgA 1
- It is 15% to 20% of the total Ig.
- It has a half-life of 6 days.
- It has paired kappa (κ) or lambda (λ) chains,
- Two heavy chains.
- IgA antibodies are produced by the plasma cells.
- The plasma cells are derived from activated B - lymphocytes.
- IgA antibodies are found in the digestive system, respiratory system, colostrum, milk, nose, eyes, and vagina.
- IgA is also found in the saliva, tears, and blood.
- IgA consists of two monomers joined by J-chain and secretory fragment.
- IgA monomer form is found in high concentration in the serum (90 to 450 mg/dL in a normal adult).
The normal structure of IgA
Functions of IgA
- IgA antibody main function is to protect the mucosa which is exposed to various antigens.
- It can activate complement by alternative pathways.
- It is effective opsonin.
- The secretory IgA consists of two 4- chain basic unit (dimeric form), joined by the J-chain.
- Deficiency of IgA leads to infection of the gastrointestinal and respiratory system.
- It has antiviral activity.
- Its major role is the protection of bacteria, viruses, and protozoal infection by preventing their attachment and colonization to the mucosa.
||1 to 4
||2 to 50
|2 to 5 month
||4 to 80
|6 to 9 month
||8 to 80
|10 to 12 month
||15 to 90
||15 to 110
|2 to 3 year
||18 to 150
|4 to 5 year
||25 to 160
|6 to 8 year
||35 to 200
|9 to 12 year
||45 to 250
||40 to 350
- To convert into SI unit x 10 = mg/L
- Adult = 85 to 385 mg/dL
- Children = 1 to 350 mg/dL
- 0 to <5 months = 7.0 to 37.0 mg/dL
- 15 to <24 months = 36 to 79 mg/dL
- 2 to <4 years = 27 to 246 mg/dL
- 10 to <13 years = 42 to 295 mg/dL
- 16 to <18 years = 60 to 337 mg/dL
- more than 18 years = 61 to 356 mg/dL
The increased level is seen in:
- Multiple Myeloma
- Cirrhosis of liver
- Systemic lupus erythematosus
- Rheumatoid arthritis
- Wiskott-Aldrich syndrome
The decreased level is seen in:
- Hereditary telangiectasia
- Type 111 dysgammaglobulinemia
- Malabsorption in some cases
- Occasional cases of Cirrhosis of liver
- Occasional cases of SLE
- Occasional cases of Still's disease
- Occasional cases of recurrent otitis media
- In Agammaglobulinemia
- Hereditary thymic aplasia
Possible References Used
Back to tests