Description
Evaluate a supplied one-site research Emax curve without fitting or clinical interpretation.
A pharmacodynamic model relates an exposure or occupancy measure to a response under explicitly supplied parameters. Baseline, maximum increment, half-maximal concentration, effect direction, and observation windows have distinct meanings. Evaluating one model term does not fit the curve or establish its clinical validity.
Evaluate a supplied one-site research Emax curve without fitting or clinical interpretation.
When to use this tool
Use Emax One Concentration Response Term when you need this particular response-model term, scale conversion, panel duration, or support calculation.
How to use the tool and how it works
- Enter concentration, ec50, maximumEffect, baseline. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read fraction, effect. Use the output convention below.
For nonnegative concentration and positive ec50 compute fraction=concentration/(ec50+concentration) using ratio branches to reduce overflow risk, then effect=baseline+maximumEffect*fraction.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| concentration | Exposure concentration in the same unit as ec50. | Required. Finite number; minimum 0. |
| ec50 | Positive concentration producing half the maximum increment under the supplied model. | Required. Finite number; strictly above 0. |
| maximumEffect | Signed asymptotic increment; final asymptote is baseline+maximumEffect. | Required. Finite number. |
| baseline | Supplied response level at the model's zero-effect baseline. | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| fraction | Dimensionless fraction under the stated basis. | Required. Finite number. |
| effect | Effect | Required. Finite number. |
{
"input": {
"concentration": 2,
"ec50": 2,
"maximumEffect": 10,
"baseline": 1
},
"output": {
"fraction": 0.5,
"effect": 6
}
}Limitations and assumptions
- Concentration and EC50 need one unit. MaximumEffect is a signed increment from baseline, not the final asymptote; no parameter fitting, individual response prediction, or dosing recommendation is performed.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Signed zero is exported as zero.
Alternative or Complementary methods
Use a fitted and validated response model when a supplied local term is insufficient. Check exposure units, response direction, baseline, model assumptions, and observation support before comparing effects.
References
Similar or alternative tools
- Sigmoid Emax Logit Slope Term
Stable supplied Hill/Emax research response and logit.
- PD Hill Curve Halfmax Residual
For positive concentration and ec50 and observedFraction in [0,1] return logConcentrationGap=ln(concentration)-ln(ec50) and halfmaxResidual=observedFraction-0.5.