In March 2015, Target Corp. alerted customers to throw out certain 10-ounce bags of organic chopped spinach because they were potentially contaminated with listeria bacteria, which can cause serious health problems.

The recall notice, filed with the U.S. Food and Drug Administration, urged people who bought the spinach to check UPC codes and a special nine-digit tracking code called the DPCI that Target includes on its sales receipts. The recall was routine, and no illnesses were publicly linked to the incident.

No such system exists for medical device consumers, however.

In fact, proposals to give insurers and patients access to the serial numbers on their implanted medical devices remain controversial.

Manufacturers say it would cost additional time and money with no guarantee of benefit to put the device serial numbers into insurance claim forms. Consumer safety officials and auditors argue the move would improve patient safety and enhance accountability.

To patient advocates like Lisa McGiffert, director of the Consumers Union's Safe Patient Project, omitting device serial numbers from an insurance claim would be like buying a car without getting its VIN number.

"We don't even have the make and the model" in insurance claims, McGiffert said. "We can put it on a car — why shouldn't we have it on a hip that you're putting in my body?"

Thousands of medical devices are recalled each year, but it can be hard to track them. In 2005, former Minnesota device maker Guidant Corp., now part of Boston Scientific, urgently recalled thousands of pacemakers because excess moisture could seep inside the life-preserving devices and ruin them.

A handful of patients with the devices went into cardiac arrest or experienced heart failure, and one death may have been linked to a pacemaker failure. Yet the Government Accountability Office (GAO) reported in 2011 that 1,732 of these recalled pacemakers were never recovered because there was "no implant record available."

Medicare, which pays hospitals to implant such devices in patients aged 65 and older, had no direct way of tracking down which of its patients may have gotten those 1,732 leaky Guidant pacemakers — nor, for that matter, any of the hundreds of thousands of other heart devices that have been recalled by the medical device industry in the years since then, critics inside and outside the government say.

Congress mandated a system of serial numbers to track medical devices known as UDIs, or unique device identifiers, back in 2007, and the Food and Drug Administration has been rolling out rules for how and when to use them ever since.

The med-tech industry and some doctors have fought hard to keep them out of Medicare claims and private insurance bills.

A two-year investigation by Medicare's inspector general office recently concluded that the publicly funded health insurer spent an estimated $1.5 billion over 10 years on surgeries and follow-up care for patients who had one of seven specific heart devices made by Minnesota manufacturers. The review did not include the Guidant pacemakers mentioned by the GAO and didn't examine other widely recalled types of devices, like metal-on-metal hip implants.

John Boujoulian, senior auditor on the Medicare inspector general investigation, said the lack of UDI numbers in Medicare claims makes it harder to locate patients affected by medical device recalls. But as it stands, Medicare would have to do a detailed review of medical records to find the UDIs to track down devices that it pays to have implanted or replaced.

"We had to go through all the medical records to find out," Boujoulian said in an interview about the audit. Using subpoenas to the device makers, "we had lists of all the people who had the medical devices implanted and the specific models, and we had to go through them all to see which ones had issues."

But going through the detailed medical records of patients is exactly what the medical device industry advocates.

"We support the collection of the UDI in the electronic health record, where it can actually be used to really help track patient outcomes and be used in a more proactive way around postmarket surveillance," said Don May, executive vice president for the Washington-based medical device manufacturer trade group AdvaMed. "If we are really concerned about patient safety, then let's go to the tool that makes the most sense."

Industry officials say the codes are too long and varied to put into insurance claims. AdvaMed says hospitals would have to invest in new bar code scanners and come up with ways to accurately transmit the data to payers. The American Medical Association says reporting UDIs in insurance claims would be cost prohibitive and insufficient for detecting widespread problems.

Organizations including Centers for Medicare and Medicaid Services and the Medicare Payment Advisory Commission have supported adding a short section of the UDI known as the "device identifier," or DI, to Medicare claims forms.

The full UDI, however, can run to 75 characters and comes in three different formats used by three different standards organizations. The full code contains not just model numbers, but batch and lot numbers, dates of manufacture and other information that would identify which specific devices are affected by problems.

AdvaMed Associate Vice President Zach Rothstein, who advocates on medical device regulation involving the FDA, said researchers who use just snippets of the UDI codes may draw inaccurate conclusions about devices that could negatively affect both medical device makers and patients.

"Think about all the food recalls where you go to your freezer and say, 'Well, was this done in that time frame and in that plant?' And the news gives you the code. It's not just this was Tyson chicken," he said. "Without [the full serial number], you just don't know."

Advocates say patient safety would benefit from the added transparency, dismissing arguments that it's too difficult or expensive. Ben Moscovitch, manager, health information technology at Pew Charitable Trusts, noted that the FDA's Sentinel program to root out problems with prescription drugs is based largely on claims data, which incorporates 10-digit National Drug Codes.

"Many of the safety challenges that occur with devices occur across the entire product line," Moscovitch said, "and to evaluate the safety of products in that capacity requires only the brand and model of the device, and not the production information that is included in the [full UDI]."

The three companies that made the recalled or defective heart devices that led to $1.5 billion in Medicare spending documented in the inspector general's report — Boston Scientific, Medtronic and St. Jude Medical owner Abbott Laboratories — all declined to comment for this story.

Asked whether the medical device companies' opposition to including UDIs in Medicare-claims forms was related to financial concerns like lost sales or increased litigation, May noted that product recalls are already costly.

"From a litigation perspective, I think malpractice attorneys are very aggressive in a lot of ways, and this just becomes one additional data source," May said. "But if you've got a product that is recalled, my guess is the company is already feeling a financial impact because it's a product that they've had to recall."

Joe Carlson • 612-673-4779