valytics (version 0.4.0)

troponin_precision: High-Sensitivity Cardiac Troponin I Precision Dataset

Description

Synthetic dataset for evaluating precision of a high-sensitivity cardiac troponin I (hs-cTnI) assay across multiple concentration levels. The data is designed for demonstrating precision studies with variance component analysis and precision profile estimation.

Usage

troponin_precision

Format

A data frame with 120 observations and 7 variables:

level

Factor. Concentration level identifier (L1 through L6).

level_label

Factor. Descriptive level label including concentration (e.g., "L1 (5 ng/L)").

concentration

Numeric. Target concentration in ng/L.

day

Factor. Day of measurement (1 through 5).

run

Factor. Run within day (1 or 2).

replicate

Factor. Replicate within run (1 or 2).

value

Numeric. Measured troponin I concentration (ng/L).

Clinical Context

High-sensitivity cardiac troponin assays are used to diagnose acute myocardial infarction (AMI). Key clinical decision points include:

• 99th percentile upper reference limit (URL): typically 14-26 ng/L

• Functional sensitivity (CV <= 10%): should be <= 50% of 99th percentile

• Precision at low concentrations is critical for early AMI detection

Details

This synthetic dataset simulates a multi-level precision study for a high-sensitivity cardiac troponin I assay. The data characteristics:

• Concentration levels: 5, 10, 25, 50, 100, 500 ng/L

• Design: 5 days x 2 runs x 2 replicates per level (EP05-style)

• Total observations: 120 (6 levels x 20 measurements each)

• Precision pattern: CV decreases with concentration following a hyperbolic relationship

The precision profile follows the model: $$CV = \sqrt{a^2 + (b/x)^2}$$

where approximately:

• \(a \approx 3\%\) (asymptotic CV at high concentrations)

• \(b \approx 25\) (concentration-dependent component)

This gives expected CVs of approximately:

• 5 ng/L: ~5.8%

• 10 ng/L: ~4.0%

• 25 ng/L: ~3.2%

• 50 ng/L: ~3.1%

• 100 ng/L: ~3.0%

• 500 ng/L: ~3.0%

See Also

precision_study() for variance component analysis, precision_profile() for CV-concentration modeling, glucose_methods, creatinine_serum, troponin_cardiac

Examples

# Load the dataset
data(troponin_precision)
head(troponin_precision)

# Precision study with multiple concentration levels
prec <- precision_study(
  data = troponin_precision,
  value = "value",
  sample = "level",
  day = "day",
  run = "run"
)
print(prec)

# Results for each concentration level
names(prec$by_sample)

# Generate precision profile
profile <- precision_profile(prec, cv_targets = c(10, 20))
print(profile)
plot(profile)

# Functional sensitivity at 10% CV
profile$functional_sensitivity