instruction: give me the number of patients who have diagnoses icd9 code v1000 and were ordered ascites fluid lab test.
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id INNER JOIN lab ON demographic.hadm_id = lab.hadm_id WHERE diagnoses.icd9_code = "V1000" AND lab.fluid = "Ascites"