ng

Ng and pg are both units of mass, but they are very different in size. A nanogram (ng) is one-billionth of a gram, while a picogram (pg) is one-trillionth of a gram. This means that a pg is 1,000 times smaller than a ng. Ng and pg are often used to measure very small quantities of substances, such as drugs, hormones, and pollutants. For example, the amount of a drug in a person’s bloodstream may be measured in ng/mL....