True negatives included misclassified annotations due to the mislinking of single protein assays to protein families. Missed deletions were also categorized as true negatives in light of this work's scope. False negatives included instances where expert knowledge was required. These were, for example, variants for which the amino acid substitution extracted matched but the sequence position was different due to sequence number shifts. Another example was constituted by completely missed substitutions because they did not correspond to the canonical regular expression. On the verge between true and false negatives were other ambiguous sequence number and amino acid substitution mismatches that did not correspond to the categories defined before. Without further manual curation, these could correspond either to potential ChEMBL miss-annotations or missed correct annotations requiring expert knowledge. In a second round of annotation following the annotation feedback loop, the defined false positives were excluded from the annotated variants and reverted to WT.