gastrointestinal tract (or GI tract) is where we digest our food. It is a long tube that runs from the mouth to the anus. The gastrointestinal tract begins with the mouth and then becomes the oesophagus (food pipe), stomach, duodenum, small intestine, large intestine (colon), rectum and, finally, the anus. It is also called the GI tract.

generic drug – drug supplied under its common (chemical) name.

genome – term for the complete genetic material (RNA or DNA) of any organism.

genotype (or genotypic) – This term has several common uses:

1. a general term for the molecular structure of a living organism or virus.

2. a test that looks at the structure of an organism of virus (ie genotype resistance test looks for changes in the virus structure – called mutations).

3. a category for different types of similar viruses – ie hepatitis C has many subtypes, referred to as genotype-1, genotype-2 etc. HCV genotype is the strongest predictor of response to hepatitis C treatment.

See also phenotype.

genotype test – a test that looks at how the genetic structure of a sample of HIV and whether the virus has changed with drug resistant mutations.

grade/grading – the grade of hepatitis infection refers to the amount of inflammation in liver tissue, found by a biopsy. It is usually measured on the Ishak scale from 1-18) where 0 is none and 18 is the maximum. See staging.