How to Calculate RFD

RfD is an acronym used in the medical industry that stands for reference dose, which describes the amount of a chemical it takes to harm someone. Specifically, it expresses the minimum amount of the chemical required before any adverse effects are expected in humans. Because of the fact that the tests used to determine RfD are done on animals rather than humans, reference doses are only a scientific estimate.

Instructions

• 1

  Find the "no observable effect level," or NOEL, of the substance. It expresses the maximum amount of chemical exposure that a test animal can endure before any effects are observed. The NOEL is usually expressed in milligrams per day.

• 2

  Divide the NOEL by 10. For example, if you found that the NOEL of your substance was 0.5 milligrams per day, you would divide 0.5 by 10 to get 0.05 milligrams per day. This calculation is meant to adjust the findings of the experiment, so they take into account the difference between the way that the animal's body reacted to the substance and the way a human would react.

• 3

  Take the quotient obtained in the prior step and divide it by 10. Using our example, this would give us 0.05 divided by 10 or 0.005. This calculation adjusts the findings, taking into account the difference between the way that one human may react to the substance versus the way that another, more sensitive one might react. The resulting number is the RfD.