Document ID: DQ130 Relevant to following products: WorkOut 2.0 Manta Document description: How To: Calculate the recovery of endotoxin spikes for LAL assays.

Setup a microplate layout with a spike group for each Unknown group. (It is assumed here that your Unknown’s are “spiked” but you could spike any group)

The calculation for the % Spike Recovery of Unknown groups is as follows:

100 * (Spike(n) - Unknown(n)) / Known Endotoxin Concentrations

For the first part of this calculation, create a Matrix Expression transform, select the input matrix to analyse and enter the expression:

100 * (Spike(n) - x)

It is case sensitive.

Next create a Dilution Factors transform, this transform is used to multiply each Unknown by a specified factor. (If you assume the dilution factor is the reciprocal of the concentration, then multiplying by a dilution factor is the same as dividing by a concentration). Therefore, enter the dilution factor for each Unknown. Under the Output tab, enter “% Spike”.