LC50 Concentration Calculator
Actual independently tested lethal concentration endpoint LC50via piecewise-linear response versus log concentration, no untested extrapolation or model-fit claim. Route/species/exposure duration and assay interpretation external; not LD50mass/bodymass or a safe concentration.
Description
An LC50 locates a fifty-percent lethal-response concentration under a specified assay.
An LC50 locates a fifty-percent lethal-response concentration under a specified assay.1
The supplied response fractions and tested concentration range determine whether an interpolated endpoint is identifiable.
When to use LC50 Concentration Calculator
Use this tool to interpolate the bracketed assay endpoint under the declared response convention. Establish the chemical, exposure route, endpoint, measurement basis and independently applicable assay or assessment reference.
How to use LC50 Concentration Calculator and understand its results
- Establish the chemical, exposure route, endpoint, measurement basis and independently applicable assay or assessment reference.
- Enter actualTestedConcentrations, independentlyAssessedLethalFractions, using the field meanings and rules below, then run the tool.
- Read observedLogInterpolatedLc50 in the tested exposure-coordinate units. Review the assay context and uncertainty separately.
- 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 |
|---|---|---|---|
| actualTestedConcentrations | Actual tested concentrations | list of number | Required |
| independentlyAssessedLethalFractions | Independently assessed lethal fractions | list of number | Required |
Require at least two aligned observations: exposure coordinates must be strictly increasing and positive, and response fractions must lie in [0,1] and be nondecreasing. The fixed target 0.5 must fall within the observed response range. A unique exact target hit returns its exposure; repeated exact target hits fail as an ambiguous plateau. Otherwise interpolate response linearly against natural-log exposure and exponentiate. No extrapolation, regression, confidence interval or automatic background correction is performed.
endpoint=exp(ln(d_i)+(ln(d_(i+1))−ln(d_i))×(0.5−p_i)/(p_(i+1)−p_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.observedLogInterpolatedLc50 | Concentration at response fraction 0.5 under log-concentration interpolation. | number |
{
"input": {
"actualTestedConcentrations": [
1,
10,
100
],
"independentlyAssessedLethalFractions": [
0.25,
0.5,
0.75
]
},
"output": {
"result": {
"observedLogInterpolatedLc50": 10
}
}
}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. Endpoint interpolation summarizes the supplied qualified assay observations; it does not supply a fitted toxicological model or an uncertainty estimate.
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 Probit Slope Calculator: A probit slope describes a relationship between independently transformed response scores and a stated dose coordinate. For a complementary comparison, use Probit Analysis Calculator: A probit-analysis record needs the fitted link, dose transformation and endpoint context.
References
-
LC50 Concentration Calculator — tool.io
Similar or alternative tools
- Probit Slope Calculator
A probit slope describes a relationship between independently transformed response scores and a stated dose coordinate.
- Probit Analysis Calculator
A probit-analysis record needs the fitted link, dose transformation and endpoint context.