Growth Inhibition MIC Endpoint

Derive the observed MIC from a monotone dilution-growth series, preserving below- and above-range censoring.

Description

The observed MIC is the lowest tested concentration with no growth under the supplied assay.

The observed MIC is the lowest tested concentration with no growth under the supplied assay. If all or none of the tested concentrations inhibit growth, the tested range censors the endpoint.^[1]

Derive the observed MIC from a monotone dilution-growth series, preserving below- and above-range censoring.

When to use Growth Inhibition MIC Endpoint

Use this tool to derive the observed MIC from a monotone dilution-growth series, preserving below- and above-range censoring.

Prepare the sample, count, growth or assay measurements requested by this tool. Confirm units, sampling periods and reporting bases; supply independently established comparison criteria where requested.

How to use Growth Inhibition MIC Endpoint and understand its results

Prepare the sample, count, growth or assay measurements requested by this tool. Confirm units, sampling periods and reporting bases; supply independently established comparison criteria where requested.
Enter concentrations, growthFlags using the field table and calculation rules, then run the tool.
Read micConcentration, endpointFound, leftCensored, rightCensored. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
concentrations	Concentrations	list of number	Required
growthFlags	Growth flags	list of number	Required

Enter aligned nonempty strictly increasing positive concentrations and nonincreasing binary growth flags. The first zero provides micConcentration; first-position zero sets leftCensored true. All growth returns concentration 0 as a placeholder, endpointFound false and rightCensored true. Flags distinguish that placeholder from a measured zero concentration.

endpoint = first concentration with growthFlag 0

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
micConcentration	Mic concentration	number
endpointFound	Endpoint found	boolean
leftCensored	Left censored	boolean
rightCensored	Right censored	boolean

json

{
  "input": {
    "concentrations": [
      1,
      2,
      4,
      8
    ],
    "growthFlags": [
      1,
      1,
      0,
      0
    ]
  },
  "output": {
    "micConcentration": 4,
    "endpointFound": true,
    "leftCensored": false,
    "rightCensored": false
  }
}

Limitations and assumptions

No interpolation or clinical interpretation is performed. Reversing growth patterns are input errors, and the assay protocol/controls are not validated. The concentration unit is caller-defined and must remain consistent.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Gradient MIC Upper Step: Round a gradient-strip MIC intersection upward to a supplied reportable dilution series; no clinical breakpoint is embedded. For a complementary task, use Bactericidal Survival Endpoint: Find the first dilution meeting a caller-defined bactericidal kill fraction based on survivor counts, rather than merely recording MBC.

References

Growth Inhibition MIC Endpoint — tool.io

Similar or alternative tools

Gradient MIC Upper Step
Round a gradient-strip MIC intersection upward to a supplied reportable dilution series; no clinical breakpoint is embedded.
Bactericidal Survival Endpoint
Find the first dilution meeting a caller-defined bactericidal kill fraction based on survivor counts, rather than merely recording MBC.