1. A computer readable medium for determining eligibility of medical claims for reimbursement, said computer readable medium comprising instructions for: sorting a set of medical claims relating to a plurality of patients according to one or more selected criteria to form one or more clusters, wherein each of said one or more clusters comprises a plurality of constituent medical claims; for each of said clusters, creating a composite medical claim representative of each respective one of said clusters; querying a benefit provider's database based on each of said composite medical claims to determine whether a patient is recognized; and for each composite medical claim for which a patient is recognized, querying said database based on each one of the respective plurality of constituent medical claims to determine whether said database contains one or more matching records that correspond at least in part to one or more fields of information in any of said respective plurality of constituent medical claims.