The Massachusetts attorney general's office says a clinical laboratory and its owner have been accused of submitting over $400,000 in Medicaid claims for unauthorized urine drug tests. The residential sobriety tests were medically unnecessary, the office said in a news release. Laboratories may not bill Medicaid for them. The Burlington-based lab and its owner were indicted last month by a statewide grand jury on two counts each of Medicaid false claims, false claims and larceny over $1,200. The lab and owner are scheduled to be arraigned in Middlesex Superior Court on March 21. It wasn’t immediately known if they had attorneys.