👉 The term "submicrogram" is used in medicine to refer to a small amount of a substance that has a very low concentration compared to other substances. Submicrograms are typically measured in parts per trillion (ppt), meaning they have one thousandth of a part per million of the concentration of a given substance. This means that submicrograms correspond to very little or no concentration of a particular substance, which is why it's often referred to as "tiny" or "substantial." Sub
