The aim of this study was to compare two methods of endotoxin testing to optimize quality control testing methodologies required for the rapid and precise determination of pyrogenicity in cell or tissue products used in cellular therapies. An automated kinetic-chromogenic method for determination of endotoxin levels in ex vivo activated T-lymphocytes infusion product, has been validated following the FDA guideline for the Limulus amebocyte lysate (LAL) assay. The validation protocol included : (1) initial qualification of the laboratory conducting the assay; (2) inhibition and enhancement tests both for treated (heated at 70 degrees C for 10 min) and untreated specimens; and (3) comparison of this assay with the conventional gel-clot method. Inhibition and enhancement testing showed that a 1:30 dilution of the infusion product was the optimal dilution for this type of specimen. Heating specimens did not appear to provide any advantage. A comparison study was performed on 105 infusion product samples. Endotoxin levels determined by both methods for all samples tested were within established end-product release specifications. The K-QCL method can be effectively used for endotoxin determination of ex vivo activated T-cells.