instruction: how many days have elapsed since patient 027-140654 has last received a anion gap lab test during the current hospital visit?
response: SELECT 1 * (STRFTIME('%j', CURRENT_TIME()) - STRFTIME('%j', lab.labresulttime)) FROM lab WHERE lab.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '027-140654' AND patient.hospitaldischargetime IS NULL)) AND lab.labname = 'anion gap' ORDER BY lab.labresulttime DESC LIMIT 1