# What is inter assay?

## What is inter assay?

The inter-assay CV is an expression of plate-to-plate consistency that is calculated from the mean values for the high and low controls on each plate, as illustrated in Example 1 below (taken from internal Salimetrics data). Most studies measure each sample in duplicate for each analyte.

## What is Intervariability?

As far as I understand, inter-variability assesses the assay-to-assay reproducibility (measuring the same samples on different days, for example), whereas intra-variability looks at the variation of sample values within a single assay run.

What is an acceptable CV%?

It is different from case to case but generally, CV value between 2% and 3% is good and acceptable. In medicine and pharmaceutical research this CV should be very low <5% or many <2% while in life sciences, e.g. agricultural sciences, CV value of 20% and even up to ≤30% could be considered acceptable.

How is CVs calculated?

The formula for the coefficient of variation is: Coefficient of Variation = (Standard Deviation / Mean) * 100. In symbols: CV = (SD/x̄) * 100. Multiplying the coefficient by 100 is an optional step to get a percentage, as opposed to a decimal.

### How is inter assay calculated?

It is expressed by intra assay coefficient of variation (intra assay CV) to monitor the deviation within the same assay. Each sample is measured several times, and then %CV is calculated for each sample by dividing the standard deviation (SD) of a set of measurements by the set mean, and multiplying by 100.

### How do you calculate inter day precision?

7. Inter-day precision can be determined by calculating the %CV at each concentration evaluated. Accuracy can be determined by comparison of the results obtained to the fortification levels. Acceptance criteria for accuracy and precision are provided in Sections 2.2 and 2.3, respectively.

How do you calculate intra assay precision?

What does CV value mean?

The coefficient of variation (CV) is the ratio of the standard deviation to the mean. The higher the coefficient of variation, the greater the level of dispersion around the mean. It is generally expressed as a percentage. The lower the value of the coefficient of variation, the more precise the estimate.

## What is an acceptable CV for precision?

Precision levels vary depending on the analyte and the method. Generally, electrolytes and creatinine have very low CV% indicating very good precision. Enzymes and immunoassays typically have higher CV%. One other rule of thumb is that a method’s CV or SD should be <1/8th of the reference range width.

What is a good coefficient of variation?

What is considered a good coefficient of variation? Basically CVgood, 10-20 is good, 20-30 is acceptable, and CV>30 is not acceptable. What does coefficient of variance tell you? The coefficient of variation (CV) is the ratio of the standard deviation to the mean.

What is intra run precision?

Intra-assay precision. Intra-assay precision reflects variability among replicate determinations within the same assay run. Each specimen is divided into a set of (usually n = 2) aliquots – and a number of sets of aliquots (N) are assayed on the same ELISA plate – in other words, a total of N × n aliquots.

03/04/2021