instruction: what was patient 031-22988's first tested specimen until 24 months ago?
response: SELECT microlab.culturesite FROM microlab WHERE microlab.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '031-22988')) AND DATETIME(microlab.culturetakentime) <= DATETIME(CURRENT_TIME(), '-24 month') ORDER BY microlab.culturetakentime LIMIT 1