DPCR Poisson Concentration

Convert digital-PCR positive partition fraction to Poisson-corrected concentration.

Description

Digital PCR occupancy can be Poisson-corrected because positive partitions may contain multiple molecules.

Digital PCR occupancy can be Poisson-corrected because positive partitions may contain multiple molecules. The negative-partition share determines the mean occupancy.^[1]

Convert digital-PCR positive partition fraction to Poisson-corrected concentration.

When to use DPCR Poisson Concentration

Use this tool to convert digital-PCR positive partition fraction to Poisson-corrected concentration.

Prepare the upstream counts, expression values, sequences or record lists requested by this tool. Keep corresponding features in the same order and confirm count units, transformations and caller-selected criteria.

How to use DPCR Poisson Concentration and understand its results

Prepare the upstream counts, expression values, sequences or record lists requested by this tool. Keep corresponding features in the same order and confirm count units, transformations and caller-selected criteria.
Enter positivePartitions, totalPartitions, partitionVolumeNl using the field table and calculation rules, then run the tool.
Read positiveFraction, meanCopiesPerPartition, copiesPerMicroliter. 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
positivePartitions	Positive partitions	number	Required
totalPartitions	Total partitions	number	Required
partitionVolumeNl	Partition volume nl	number	Required

Supply positive total partitions and volume nL with nonnegative positives strictly below total. Use log1p for occupancy and return positive fraction, mean copies per partition and concentration. Zero positives gives zero; all-positive partitions are rejected because the finite estimate diverges.

λ=−ln(1−positive/total); copiesPerµL=1000 λ/partitionVolumeNl

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

Output field	Meaning	Value type
positiveFraction	Positive fraction	number
meanCopiesPerPartition	Mean copies per partition	number
copiesPerMicroliter	Copies per microliter	number

json

{
  "input": {
    "positivePartitions": 500,
    "totalPartitions": 1000,
    "partitionVolumeNl": 1
  },
  "output": {
    "positiveFraction": 0.5,
    "meanCopiesPerPartition": 0.6931471805599453,
    "copiesPerMicroliter": 693.1471805599452
  }
}

Limitations and assumptions

Equal partition volume, random loading and accurate positive calls are assumed. This does not provide confidence intervals, dilution correction or diagnostic interpretation; fractional partition values are accepted by the schema.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Pfaffl Expression Ratio: Calculate Pfaffl expression ratio with independent primer efficiencies. For a complementary task, use Bioanalyzer Concentration: Interpolate sample concentration from a caller-supplied Bioanalyzer ladder peak.

References

DPCR Poisson Concentration — tool.io

Similar or alternative tools

Pfaffl Expression Ratio
Calculate Pfaffl expression ratio with independent primer efficiencies.
Bioanalyzer Concentration
Interpolate sample concentration from a caller-supplied Bioanalyzer ladder peak.