Toxic Units Mixture Calculator

Actual mixture concentration/independently verified compatible single-component endpoint toxic units, summed only under declared concentration-addition/common-endpoint assumptions. Not the existing Hillresponse curve, independent-action model or mixture hazard certification.

Description

Mixture toxic units can be summed under a declared concentration-addition model with compatible endpoints.

Mixture toxic units can be summed under a declared concentration-addition model with compatible endpoints.^[1]

That assumption does not describe every interaction between mixture components.

When to use Toxic Units Mixture Calculator

Use this tool to calculate or review the supplied observations under the stated rules. Establish the chemical, exposure route, endpoint, measurement basis and independently applicable assay or assessment reference.

How to use Toxic Units Mixture Calculator and understand its results

Establish the chemical, exposure route, endpoint, measurement basis and independently applicable assay or assessment reference.
Enter actualMixtureConcentrations, callerVerifiedMatchedEndpointConcentrations, using the field meanings and rules below, then run the tool.
Read result.observedComponentToxicUnits, result.conditionalConcentrationAdditionToxicUnits. Use the units and subtraction order below to interpret each value; retain negative differences where returned.
Correct any reported input issue and run again. Before using a successful result, check the stated units, signs, reference scope and observation coverage.

Input field	Meaning	Value type	Requirement
actualMixtureConcentrations	Actual mixture concentrations	list of number	Required
callerVerifiedMatchedEndpointConcentrations	Caller verified matched endpoint concentrations	list of number	Required

Supply nonempty aligned nonnegative measured concentrations and strictly positive compatible endpoint concentrations. Divide each concentration by its endpoint and sum those individual toxic units. The calculation assumes the declared additive screening convention rather than establishing interaction or a mixture effect.

toxicUnit_i=concentration_i/endpoint_i; summedToxicUnits=ΣtoxicUnit_i

Use the matching field units and the exact boundary, ordering and reference rules above.

Output field	Meaning	Value type
result	Qualified observed calculation or explicit reference	object
result.observedComponentToxicUnits	Each measured concentration divided by its matched endpoint concentration.	list
result.conditionalConcentrationAdditionToxicUnits	Sum of the component concentration/endpoint ratios under the declared additive convention.	number

json

{
  "input": {
    "actualMixtureConcentrations": [
      1,
      2
    ],
    "callerVerifiedMatchedEndpointConcentrations": [
      2,
      4
    ]
  },
  "output": {
    "result": {
      "observedComponentToxicUnits": [
        0.5,
        0.5
      ],
      "conditionalConcentrationAdditionToxicUnits": 1
    }
  }
}

Limitations and assumptions

Chemical identity, route, assay, exposure basis and reference applicability are caller-established. The output supplies no causal conclusion, universal toxicity threshold or authoritative regulatory determination.

Missing required fields, unknown fields, wrong types and violated rules return input issues. Numeric values and outputs must be finite. Lists and matrices must be dense, without missing cells. Numeric lists allow at most 10000 entries, subject to the narrower lengths and code rules above. Extremely large composite outputs are rejected.

Alternative or Complementary methods

For a related step, use Toxicity Units Calculator: A toxic unit normalizes a measured concentration by a matched endpoint concentration. For a complementary comparison, use Relative Potency Factor Calculator: Relative potency can vary across matched effect levels when response relationships are not parallel.

References

Toxic Units Mixture Calculator — tool.io

Similar or alternative tools

Toxicity Units Calculator
A toxic unit normalizes a measured concentration by a matched endpoint concentration.
Relative Potency Factor Calculator
Relative potency can vary across matched effect levels when response relationships are not parallel.