instruction: calculate the number of patients who have received a laboratory test for bicarbonate this year.
response: SELECT COUNT(DISTINCT patient.uniquepid) FROM patient WHERE patient.patientunitstayid IN (SELECT lab.patientunitstayid FROM lab WHERE lab.labname = 'bicarbonate' AND DATETIME(lab.labresulttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year'))