Tokyo Metropolitan Government health officials questioned staff at a hospital and a clinical testing company Friday over incorrect medical data given to more than 10,000 patients over a six-month period beginning April.
The Public Health Bureau officials spoke with staff and inspected the laboratory at Tokyo Rinkai Hospital in Edogawa Ward.
On Thursday, it was learned that 20,176 blood test samples from around 10,300 people were wrongly evaluated by Tokyo-based testing company SRL Inc.
SRL, listed on the first section of the Tokyo Stock Exchange, revealed Friday that evaluation data on seven types of tests -- including those for liver, pancreas and heart functions -- were reported between 8 percent and 36 percent higher than they should have been between April 1 and Oct. 10, because evaluation parameters had been incorrectly set.
Four officials of the bureau's medical safety team visited the hospital in the morning and inspected laboratory equipment and questioned staff, according to government officials.
On Thursday, sources said SRL adjusted its blood test equipment improperly, providing incorrect data to about 7,900 hospitalized patients and 2,400 patients who received medical checkups. Some 100 were being told their blood was "abnormal" when in fact it was fine, they said.
SRL owned up to its mistakes and decided to send a letter of apology to all patients who received erroneous reports, the sources said.
The company discovered the mistakes in September, they said.
"We sincerely apologize to the patients," an SRL official said in admitting the mistakes, adding, "There were no mistakes at other hospitals."
A hospital official said there were probably no serious effects on medical examinations following the tests because the data were produced based on more rigorous criteria than normal.