instruction: what was the first specimen test of patient 031-22988 until 03/2104?
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 STRFTIME('%y-%m', microlab.culturetakentime) <= '2104-03' ORDER BY microlab.culturetakentime LIMIT 1