Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:A subset of patients (n = 74) were screened for the multiple endocrine neoplasia 1 (MEN1) gene using direct bidirectional sequencing and multiplex ligation-dependent probe amplification.(19) In addition, 36 patients had stored urine samples collected before undergoing TSS; in these samples, spot urine calcium and creatinine were measured using the Dimension Clinical Chemistry system (Siemens Healthcare Diagnostics, Tarrytown, New York).
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