Immunochromatographic technique (ICT)

Details of ICT

1. Immunochromatographic Technique Basir Ahmad MLT 1

2. Outlines Introduction Principle Components Procedure Result interpretation Test names 2

3. Introduction Lateral flow tests also known as lateral flow  immunochromatographic assays, are simple devices intended to detect the presence (or absence) of a target analyte in sample (matrix) without the need for specialized and costly equipment 3

4. Principal of immunochromatography kit   Principal of immunochromatography is the same as ELISA sandwich method, only difference is in that immunological reaction is carried out on the chromato - graphic paper by capillary action.     4

5.   For this system, two kinds of specific antibodies against antigen are used. One of the antibodies is immobilized on  the chromatographic paper other is labeled with colloidal gold and  infiltrated into sample pad An  imunochromatographic unit is completed by  attaching the sample pad at the end of the membrane. 5

6. Liquid sample is dropped on the sample pad The antigen in the sample forms an immunocomplex with the antibody labeled with colloidal gold. Its complex moves along with the liquid sample  and makes a contact with the antibody immobilized on the membrane followed by forming an immuno - complex with the immobilized antibody, 6

7. Resulting in generating a colored red purple line. Appearance of red purple line on the membrane indicates the presence of antigen of interest in the sample Liquid of the sample migrates through the membrane very fast, it makes it possible to detect the presence or absence of antigen within 15 minutes 7

8. Components 8

9. Sample pad : Acts as a sponge and holds an excess of sample fluid. Once soaked, the fluid migrates to the second element Conjugate pad:A dried format of bio-active particles in a salt-sugar matrix that contains everything to guarantee an optimized chemical reaction between the target molecule (e.g., an antigen) and its chemical partner (e.g., antibody) that has been immobilized on the particle's surface 9

10. Control :It contains an antibody that picks up free latex/gold in order to confirm the test has operated correctly. Test : It contains a specific capture molecule and only captures those particles onto which an analyte molecule has been immobilized 10

11. Procedure Take an alcohol swab and disinfect the site of prick. Take a pricker and puncture the area below finger tip. Ooze the blood . Take two drops with sucker and dispensed in sample hole of strip. Add buffer to sample. 11

12. Wait for 10-15 min Observe result and interpret accordingly 12

13. Result interpretation 13

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15. Good and Bad of ICTs ICTs are a promising tool for reliable level of diagnostic performance. Simple Rapid assays that can be completed in 10-15 min. They reduce the need for trained examiners and costly equipment. It can be used under harsh field conditions. 15

16. ICT assays are not as sensitive as other immunoassays Note that the results should be confirmed by other reference tests 16

17. Test names Typhidot Pregnancy HBs Ag HCV Ab HIV Parasites 17

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