LAL test specificity. According to the acceptance criteria, the histogram shows that the mean spike recovery of three replicates for all samples analysed was between 0.25 EU/ml and 1EU/ml (A) with PPC CV% less than 10 (B). Bars are SD. Samples analysed are given in Table 1. Samples: 1 = pyrogen free water (negative control); 2–10 = supernatants with FBS; 11–13 = supernatants with albumin; 14–17 = CTPs; 18–23 = supernatants with HS.