Description
For positive concentration and ec50 and observedFraction in [0,1] return logConcentrationGap=ln(concentration)-ln(ec50) and halfmaxResidual=observedFraction-0.5.
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.
For positive concentration and ec50 and observedFraction in [0,1] return logConcentrationGap=ln(concentration)-ln(ec50) and halfmaxResidual=observedFraction-0.5.
When to use this tool
Use PD Hill Curve Halfmax Residual 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, observedFraction. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read logConcentrationGap, halfmaxResidual. Use the output convention below.
For positive concentration and ec50 and observedFraction in [0,1] return logConcentrationGap=ln(concentration)-ln(ec50) and halfmaxResidual=observedFraction-0.5.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| concentration | Exposure concentration in the same unit as ec50. | Required. Finite number; strictly above 0. |
| ec50 | Positive concentration producing half the maximum increment under the supplied model. | Required. Finite number; strictly above 0. |
| observedFraction | Supplied dimensionless response fraction in [0,1]. | Required. Finite number; minimum 0; maximum 1. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| logConcentrationGap | Log Concentration Gap | Required. Finite number. |
| halfmaxResidual | Halfmax Residual | Required. Finite number. |
{
"input": {
"concentration": 2,
"ec50": 2,
"observedFraction": 0.6
},
"output": {
"logConcentrationGap": 0,
"halfmaxResidual": 0.09999999999999998
}
}Limitations and assumptions
- Concentration and EC50 need the same unit. This compares two supplied half-maximal anchors without fitting a Hill coefficient, predicting response, or validating the observed fraction.
- 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.
- Emax One Concentration Response Term
Evaluate a supplied one-site research Emax curve without fitting or clinical interpretation.