VFP-Package: (V)ariance (F)unction (P)rogram

In VFP: Variance Function Program

(V)ariance (F)unction (P)rogram

Description

The intended use of this package is to implement variance functions proposed in Sadler's VFP stand-alone software (see reference below), from which the name was borrowed as well. Main function of this package is fit.vfp for fitting non-linear variance-function models. Usually, these models are fitted to analysis-results of precision performance data e.g. frequently generated for in-vitro diagnostics (IVD). R-package VFP is designed to work best on objects of class 'VCA' as generated by R-package VCA but it is not restricted to these. There are several functions operating on S3-objects of class 'VFP', e.g. plot.VFP, print.VFP, summary.VFP, and predict.VFP. Function predictMean is of special interest when a functional relationship is used to derive limit of quantitation (LoQ) or functional sensitivity, as the concentration at which the IVD-imprecision expressed as coefficient of variation (CV) undercuts a specific threshold.

Details

Package:	VFP
Type:	Package
Version:	1.4.4
Date:	2025-04-08
License:	GPL (>=3)
LazyLoad:	yes

Author(s)

Andre Schuetzenmeister [e-mail], Florian Dufey [e-mail], Andrea Geistanger [e-mail]

References

CLSI EP05-A3: Evaluation of Precision of Quantitative Measurement Procedures; Approved Guideline - Third Edition. (2014)

Sadler WA, Smith MH. Use and Abuse of Imprecision Profiles: Some Pitfalls Illustarted by Computing and Plotting Confidence Intervals. Clin Chem 1990; 36/7:1346-1350

Sadler WA, Smith MH. A reliable method of estimating the variance function in immunoassays. Comput Stat Data Anal 1986; 3:227-239

Sadler WA, Smith MH. Estimation of imprecision in immunoassays quality assessment programmes. Ann Clin Biochem 1987; 24:98-102

www.aacb.asn.au/AACB/Resources/Variance-Function-Program

VFP documentation built on April 13, 2025, 5:12 p.m.