You see, itâs actually the distance from the subject. The focal length is an indicator of the distance from the subject: the images are all framed the same; differences arise because the focal length is getting longer (zooming in) as the camera moves further away from the subject.
Normal values range from 0.4 to 4.0 milli-international units per liter (mIU/L). 1  TSH values can vary during the day. It is best to have the test early in the morning.  Experts do not fully agree on what the upper number should be. Opinions vary from 2.5 to 4.0 mIU/L.
A TSH test is a lab test that analyzes your blood to determine the body's overall TSH levels. If you begin to show signs of a malfunctioning thyroid your doctor my order a test to check for the TSH levels in your system. If these show a high level of TSH you may have a sluggish thyroid, but low levels of TSH signal that your thyroid may be overactive.