Blank Fold Filter

Filter features by sample-to-blank peak-area ratio.

Description

A blank-fold filter compares paired sample and blank responses.

A blank-fold filter compares paired sample and blank responses. An inclusive fold threshold selects zero-based feature indexes.^[1]

Filter features by sample-to-blank peak-area ratio.

When to use Blank Fold Filter

Use this tool to filter features by sample-to-blank peak-area ratio.

Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.

How to use Blank Fold Filter and understand its results

Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.
Enter sampleAreas, blankAreas, minimumFold using the field table and calculation rules, then run the tool.
Read sampleBlankFolds, retainedIndexes. 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
sampleAreas	Sample areas	list of number	Required
blankAreas	Blank areas	list of number	Required
minimumFold	Minimum fold	number	Required

Enter nonempty aligned nonnegative sample areas, positive blank areas and nonnegative minimum fold. Return ratios and selected indexes in input order.

fold_i=sample_i/blank_i; selected if fold_i≥minimum

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

Output field	Meaning	Value type
sampleBlankFolds	Sample blank folds	list of number
retainedIndexes	Retained indexes	list of number

json

{
  "input": {
    "sampleAreas": [
      10,
      30,
      5
    ],
    "blankAreas": [
      1,
      10,
      2
    ],
    "minimumFold": 5
  },
  "output": {
    "sampleBlankFolds": [
      10,
      3,
      2.5
    ],
    "retainedIndexes": [
      0
    ]
  }
}

Limitations and assumptions

No blank pooling, noise model or contaminant identification is performed.

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.

Alternative or Complementary methods

Use Carryover Residual: Measure blank-after-high calibrator carryover percentage. For a complementary task, use Pooled QC Cv Gate: Gate pooled metabolomics QC by coefficient of variation.

References

Blank Fold Filter — tool.io

Similar or alternative tools

Carryover Residual
Measure blank-after-high calibrator carryover percentage.
Pooled QC Cv Gate
Gate pooled metabolomics QC by coefficient of variation.