The RIVA is more sterile and less prone to contamination than using human pharmacists, and it's built to be adept at spotting potential errors, said Doherty. After medications are loaded by a technician, the camera scans drug labels for names, doses and expiration dates. The balance weighs vials and syringes to establish their weights, while the robotic arm and laser sensor measures how large the syringes are.

All told, 3% to 4% of drugs being combined by RIVA are rejected before they are completed due to discrepancies, with data being captured in the software-equivalent of a black box in case of errors.

Drug-related errors sometimes bubble up into the news. In 2006, the newborn twins of actor Dennis Quaid almost died when they were accidentally given 1,000 times the dosage of a blood thinner called heparin. Quaid is suing heparin's maker, Baxter Healthcare, for negligence, arguing that its packaging did not differentiate enough between dosages. He's also testified before Congress on the topic ( ).

So far, no hospitals have reported any incorrect doses created by RIVA, Doherty said. That's in part because live pharmacists remain the ultimate gatekeeper. "We will never replace having the pharmacist check the final order and approve the prescription," Doherty said.

To further cut down on the risk of errors, RIVA can connect with computerized physician order entry (CPOE) systems that require a doctor to choose and confirm a drug via computer rather than scribble the prescription on a notepad. And it works with bar-code medication administration (BCMA) systems that confirm when medicines are given, Doherty said.