Introduction of Aspergillus Galactomannan ELISA Detection Kit

Galactomannan (GM) is a polysaccharide that is present in the cell wall component of Aspergillus species. It is released into the blood during fungal growth in the tissue that can be detected by Enzyme-Linked Immunosorbent Assay (ELISA).

Principle of ELISA

ELISA stands for Enzyme-Linked Immunosorbent Assay. It comes under antigen and antibody reaction tests and is useful for the identification of antigens or antibodies of following specimens serum and BAL (in the case of Mycology). It is also applicable for qualitative as well as quantitative determination of antigens or antibodies. In qualitative test determines antigen or antibody is present or absent whereas in quantitative determines the quantity of the antibody in titer and the titer is the highest dilution of the specimen usually serum which gives a positive reaction in the test. (For more details, follow the link: https://medicallabnotes.com/enzyme-linked-immunosorbent-assayelisa-introduction-principle-types-procedure-result-interpretation-advantage-disadvantage-and-interfering-factors-of-elisa-test-results/)

Aspergillus Galactomannan ELISA Detection Kit Characteristics

Product characteristics are described in a table-

	Serum	bronchoalveolar lavage (BAL)
Sensitivity	89.8%	92.4%
Specificity	90.7%	94.1%
Sample type	Serum, BAL
Sample volume	300 µL
Specification	96 tests/kit
Detection time	2 hours
Limit of Detection	0.5 ng/ml
Inter-assay variation	≤15%
Instrument	Microplate Reader

Keynotes

• FungiXpert® Aspergillus Galactomannan ELISA Detection Kit is a product of bio-state Inc.
• Product advantages are as follows-

1. Advance
2. Accurate
3. Faster
4. Economical

• Types of ELISA –

1. Direct ELISA (sandwich ELISA -For Ag detection),
2. Indirect ELISA (For Ab detection),
3. Competitive ELISA, and
4. Capture ELISA.

• Direct ELISA is for the detection of antigens.
• Indirect ELISA is for the detection of antibodies.
• Sandwich or Competitive ELISA is for the detection of antigens.
• The invalid test should be repeated.
• FungiXpert® Aspergillus Galactomannan ELISA Detection Kit is a sandwich ELISA for the detection of Aspergillus galactomannan antigen in serum and BAL clinical specimens to help in the diagnosis of invasive aspergillosis.
• FungiXpert® Aspergillus Galactomannan ELISA Detection Kit has the following benefits-

1. Rapid and accurate results within 2 hours
2. Convenient-Its reagents are ready-to-use.
3. Flexible: It has breakable strips that offer flexibility for Galactomannan immunoassay.

Interfering Factors of ELISA Test Results

The following factors which affect the ELISA result are as follow as-

1. Plate Assay: the shape and quality of the wells, the material of the plate, potential pre-activation, even or uneven coating
2. Buffer: pH, contamination
3. Capture and detection antibody: incubation time, temperature, specificity, titer, affinity
4. Blocking Buffer: cross-reactivity, concentration, contamination
5. Target antigen: conformation, stability, epitopes
6. Enzyme conjugate: type, concentration, function, cross-reactivity
7. Washes: contamination, frequency, volume, duration, composition
8. Substrate: quality/manufacturer
9. Detection: instrument-dependent factors
10. The reader or human error

Advantages of ELISA

• Specific and sensitive with wide application
• Equipment is cheap and easily available.
• Reagents are “Cheap” and have a long shelf life.
• Assays may be rapid.
• Simultaneous assay, variety of labels
• Potential for automation
• No radiation hazards

Disadvantages of ELISA

• Contamination
• Expertise required to label and purify conjugates
• Susceptible to interference from non-specific factors

Further Readings

1. https://erabiocanada.com/fungixpert-aspergillus-galactomannan-elisa-detection-kit/
2. https://www.immunology.org/public-information/bitesized-immunology/experimental-techniques/enzyme-linked-immunosorbent-assay
3. https://www.who.int/diagnostics_laboratory/faq/elisa/en/
4. http://www.biobest.co.uk/diagnostics/techniques/elisa-how-does-the-test-work.html
5. https://www.ncbi.nlm.nih.gov/books/NBK555922/
6. https://stanfordhealthcare.org/medical-conditions/sexual-and-reproductive-health/hiv-aids/diagnosis/elisa.html
7. Textbook of Medical Laboratory Technology by Praful B. Godkar, Darshan P. Godkar
8. https://www.sciencedirect.com/topics/immunology-and-microbiology/elisa
9. Textbook of Medical Laboratory Technology by Ramnik Sood (2006)