This happens about 2-3% of the time in people with celiac disease and can lead to false-negative test results. Common tests for celiac disease include: 1  Anti-tissue transglutaminase antibody (anti-tTG), IgA: detects antibodies to tissue transglutaminase, an enzyme that causes the crosslinking of certain proteins. 2  Anti-tTG, IgA is the most sensitive and specific blood test for celiac disease.
A contour line is a line drawn on a topographic map to indicate ground elevation or depression. A contour interval is the vertical distance or difference in elevation between contour lines. Index contours are bold or thicker lines that appear at every fifth contour line.
These are lines drawn on maps that join places of the same height. They are usually an orange or brown colour. Some contour lines have their height above or below sea level written on them.It is possible to use them to see the shape of the land-if contour lines are close together the slope is steep, if they are far apart the slope is gentle.Contour lines are usually drawn at 10 metre intervals on a 1:50,000 scale map and at 5 metre intervals on a 1:25,000 scale map.Credit : Â© Crown copyright.hese are lines drawn on maps that join places of the same height. They are usually an orange or brown colour. Some contour lines have their height above or below sea level written on them.