State faults St. Agnes lab procedures
The city medical examiner finds two deaths were directly related to faulty tests.
By Michael Rubinkam
A hospital laboratory failed to follow proper procedures when performing a routine diagnostic test, leading some patients to receive incorrect doses of a blood-thinning medication and causing two deaths, the state health department said today.
Officials at St. Agnes Medical Center have said 932 patients may have received incorrect doses of the anticoagulant warfarin, better known by the brand name Coumadin, between June 4 and July 25 because of a laboratory miscalculation.
Warfarin is prescribed for patients with artificial heart valves, abnormal heart rhythms and other conditions that increase the risk of blood clots. A blood clot can lead to a heart attack or a stroke.
Philadelphia Medical Examiner Dr. Haresh Mirchandani ruled Wednesday that the lab errors resulted in two deaths. Vincent Arguto and Louis Vitello died after sufferering "intracranial hemorrhage," Mirchandani said. The medical examiner ruled the deaths accidental.
Three other patients originally thought to have died as a result of the lab error all died of natural causes, Mirchandani said.
The health department said the lab error involved the prothrombin time test, which measures blood thickness and is typically used to monitor patients using warfarin.
"It was clear from the start that an incorrect formula number was used, causing an error in the calculation of the prothrombin test," Health Secretary Robert S. Zimmerman Jr. said. "That error resulted in patients receiving a higher dosage of an anticoagulant drug."
As a result of the findings, the health department issued St. Agnes a "condition-level deficiency," meaning that the department cannot vouch for the accuracy of the hospital's prothrombin tests. The laboratory has 10 days to fix the problems or risk losing authorization to perform clinical diagnostic testing.
St. Agnes voluntarily stopped doing the test soon after the errors were discovered and has been sending the work to another lab.
Hospital officials scheduled an afternoon news conference to discuss the findings.
The health department investigation centered on the main chemical used in the prothrombin test, fibrinogen, which is added to blood in a machine and causes it to clot.
The hospital ordered what it thought was a more sensitive version of fibrinogen, but instead received a less sensitive version, according to Dr. Bruce Klegerd, director of the Bureau of Laboratories for the state health department. The lab did not discover the error and then used the wrong formula to calculate the clotting of patients' blood, he said.
"People got wrong results and medication was adjusted based on these incorrect results. They were given a higher dosage," Klegerd said.
The health department investigation found errors in the hospital's ordering procedure for fibrinogen and said the lab's quality assurance program should have detected the mistake.
"The error ranks up there because it affected so many people and it went on for so long. This particular type of error in a laboratory, it is very rare. You don't see it happening," health department spokesman Richard McGarvey said on WCAU-TV.
The health department also noted "concerns" about the labeling of the fibrinogen and contacted the U.S. Food and Drug Administration, which is responsible for product labeling.
It's unclear whether the St. Agnes patients were taking Coumadin or a generic equivalent.
The department said it investigated every other diagnostic test performed by St. Agnes that uses a formula calculation and found no other problems.
Nevertheless, the department said it will conduct unannounced checks of St. Agnes' lab procedures over the next year to make sure the hospital is in compliance.