Gravindex
{{Short description|Test performed to detect pregnancy}}
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Gravindex is an agglutination inhibition test performed on a urine sample to detect pregnancy.{{Cite book |url=https://books.google.com/books?id=ciDQAAAAMAAJ |title=MCH Research Series |date=1974 |publisher=Health Services Administration, Bureau of Community Health Services. |pages=8–9 |language=en}} It is based on double antigen antibody reaction. The test detects the prevention of agglutination of HCG-coated latex particles by HCG present in the urine of pregnant women.{{Cite book |last1=Khurana |first1=Indu |url=https://books.google.com/books?id=Q-18EAAAQBAJ |title=Concise Textbook of Human Physiology - E-Book |last2=Khurana |first2=Ayushi |date=2022-07-06 |publisher=Elsevier Health Sciences |isbn=978-81-312-6474-4 |pages=422 |language=en}}
Procedure and results
Kits commercially available contain two reagents; one is a suspension of HCG-coated latex particles, and the other is a solution of HCG antibodies. One drop of the urine is mixed with one drop of antibody solution for one minute on a black glass slide. One drop of the HCG-coated latex particles is added to the slide and left for one minute.
- If the level of HCG is too low, the antibodies will remain to agglutinate the HCG-coated latex particles. If agglutination occurs, the subject is not pregnant.
- If the level of HCG is high, the HCG will bind to the antibodies, and thus no agglutination with the HCG-coated latex particles occurs. If no agglutination occurs, the subject is pregnant.
References
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