What is the uncertainty factor?

Definition: A number (equal or greater than 1) used to divide NOAEL or LOAEL values derived from measurements in animals or small groups of humans, in order to estimate a NOAEL or LOAEL value for the whole human population; also called margin-of-safety.

How do you calculate uncertainty factor?

The general formula for deriving the RfD is: RfD = NOAEL or LOAEL UF1 x UF2 x … The more uncertain or unreliable the data becomes, the higher will be the total uncertainty factor that is applied.

What is NOAEL in toxicology?

The no-observed-adverse-effect-level (NOAEL) is an important part of the non-clinical risk assessment. It is a professional opinion based on the design of the study, indication of the drug, expected pharmacology, and spectrum of off-target effects. There is no consistent standard definition of NOAEL.

How is uncertainty factored into an overall risk assessment?

Uncertainty in risk assessment can be present in the characterization of the exposure scenario, the parameter estimates, and model predictions. For example, grouping individuals with unique measured exposure levels into categories of exposure ranges can introduce aggregation errors and subsequent uncertainty.

What is uncertainty in statistics?

Uncertainty in statistics is measured by the amount of error in an estimate of the mean or average value of a population.

How is the NOAEL determined?

NOAEL (No Observed Adverse Effect Level), determined by toxicity studies etc., is divided by UFs (product of Uncertainty Factors)*3 to convert it to human NOAEL. (e.g., mg/kg/day). ADI (Acceptable Daily Intake) and RfD (Reference Dose) are also used as terms having the same meaning as TDI.

What is NOAEL a measure of?

No-observed-adverse-effect level (NOAEL) Greatest concentration or amount of a substance, found by experiment or observation, which causes no detectable adverse alteration of morphology, functional capacity, growth, development or life span of the target organism under defined conditions of exposure.

What is uncertainty risk?

Risk refers to decision-making situations under which all potential outcomes and their likelihood of occurrences are known to the decision-maker, and uncertainty refers to situations under which either the outcomes and/or their probabilities of occurrences are unknown to the decision-maker.

What is an example of uncertainty?

Uncertainty is defined as doubt. When you feel as if you are not sure if you want to take a new job or not, this is an example of uncertainty. When the economy is going bad and causing everyone to worry about what will happen next, this is an example of an uncertainty.

Does NOAEL measure chronic toxicity?

Higher NOAEL or NOAEC indicates lower systemic toxicity or lower chronic toxicity.