In nature, methane is produced by the anaerobic bacterial decomposition of vegetable matter under water (where it is sometimes called marsh gas or swamp gas). Wetlands are the major natural source of methane produced in this way.
What are the exams and tests for renal artery stenosis? Blood tests. Screening blood tests may be done as part of the general evaluation of high blood pressure and may include a complete blood count, electrolytes, kidney function tests, and a urinalysis. Imaging. Renal artery narrowing can be detected with ultrasound or computerized tomography angiography or arteriography.
This can occur if the artery blocks off suddenly, or more gradually if there is a serious narrowing. In its early stages, kidney failure does not cause symptoms, but is only detected in blood tests. The prevention of kidney failure is one of the main aims when doctors treat renal artery stenosis. High blood pressure  One of the jobs the kidneys normally perform is to control the blood pressure. If they are starved of blood, this can cause high blood pressure.