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Carryover Assessment

Source: R/accuracy.R
measure_carryover.Rd

Evaluates carryover by analyzing blank samples run after high-concentration samples.

Usage

measure_carryover(
  data,
  response_col,
  sample_type_col,
  run_order_col,
  blank_type = "blank",
  high_type = "high",
  threshold = 20,
  lloq = NULL
)

Arguments

data

A data frame containing the run sequence with blanks after highs.

response_col

Name of the column containing response values.

sample_type_col

Name of the column identifying sample types.

run_order_col

Name of the column containing run order.

blank_type

Value identifying blank samples. Default is "blank".

high_type

Value identifying high-concentration samples. Default is "high".

threshold

Carryover threshold as percentage of LLOQ or high response. Default is 20 (meaning 20% of LLOQ).

lloq

Optional LLOQ value for threshold calculation.

Value

A measure_carryover object containing:

  • blank_responses: Response values in blanks after high samples

  • mean_blank: Mean blank response

  • max_blank: Maximum blank response

  • high_responses: High sample responses

  • carryover_pct: Carryover as percentage of high or LLOQ

  • pass: Whether carryover is within acceptable limits

Details

Carryover is the appearance of analyte in a blank sample due to contamination from a previous high-concentration sample. It is typically assessed by analyzing blank samples immediately after the highest calibration standard or QC sample.

Acceptance Criteria (ICH M10)

Carryover in the blank sample following the high concentration should not exceed:

  • 20% of the LLOQ (for the analyte)

  • 5% of the internal standard response

See also

measure_accuracy(), measure_system_suitability()

Other accuracy: measure_accuracy(), measure_linearity()

Examples

# Carryover assessment
data <- data.frame(
  run_order = 1:10,
  sample_type = c("std", "std", "std", "high", "blank",
                  "qc", "qc", "high", "blank", "std"),
  response = c(100, 500, 1000, 5000, 5, 500, 510, 4900, 8, 100)
)

result <- measure_carryover(
  data,
  response_col = "response",
  sample_type_col = "sample_type",
  run_order_col = "run_order",
  lloq = 50
)
print(result)
#> measure_carryover
#> ──────────────────────────────────────────────────────────────────────────────── 
#> 
#> Evaluation:
#>   High-blank pairs: 2 
#>   Mean high response: 4950 
#>   Mean blank response: 6.5 
#>   Max blank response: 8 
#> 
#> Carryover:
#>   Reference (LLOQ):50
#>   Carryover: 16 % of LLOQ 
#>   Threshold: 20 %
#> 
#> Result: PASS