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Tissue factor

The Tissue Factor (TF) is defined as the ratio of extraction solvent volume to tissue volume (see equation 1). For this the following assumption is made: 1 mg tissue = 1 µL extraction solvent.

  1. TF = µL extraction solvent / µL tissue

In order to calculate the Normalization Ratio (NR) the total extraction volume is taken into account. The Normalization Ratio (NR) is calculated according to equation 2.

  1. NR = (TF + 1 µL tissue) / 1 µL tissue = (TF + 1) / 1

According to equation 3, the Normalization Ratios are used to calculate the normalized analyte concentration (c).

  1. cnormalized(analyte) = NR x c(analyte)

Normalized concentrations are displayed in Results section. Navigate to Results > Display Options > Concentration unit and choose the option pmol/mg Tissue from the dropdown menu. The Tissue Factor normalization usage is described in more detail below.

Display options

Tissue factor example​

The tissue factors for each sample can be defined in LIMS > Sample registration > Tissue and cell factors.

A value of 0 is entered by default and no normalization will be executed. Using pre-extracted samples, please enter a value apart from 0. For example, if you have added the a 120 µL volume of extraction solvent to 30 mg of tissue, enter 4 as the tissue factor.

As the tissue volume must be taken into account, the Normalization Ratio (NR) is calculated according to equation 4.

  1. NR = (TF + 1) / 1 = (4 + 1) / 1 = 5

cnormalized(analyte) = NR x 5

Subsequent tissue factor normalization​

For subsequent data normalization after data has already been processed in WebIDQ, please select the corresponding plate-run in LIMS and Delete measurements. Afterwards enter the tissue factor values and re-import your corresponding data files again.