Amid a surge in testing demand, the state has informed Maine’s hospitals that it will no longer process their COVID-19 tests at the state laboratory after Thursday.

The Department of Health and Human Services informed the state’s hospitals of the decision in a Tuesday morning email obtained by the Press Herald. The email said the agency had come to the sudden decision after the increasing demand “placed a strain on the ability of the laboratory to process samples for emergent situations such as outbreaks.”

The email, from testing director Sally Weiss, said the change means the lab “will not be able to accept or process samples from hospitals for pre-procedural/pre-operative testing, not testing of inpatients or outpatients,” though the lab will continue to process samples from the “swab and send” sites it set up at some hospitals. Six of the state’s 36 hospitals rely on the lab for most of their testing, but it was not clear how many daily tests they require.

The change, which highlights the stress that the unprecedented spike in COVID-19 cases is having on the state’s health infrastructure, caught the state’s hospitals by surprise, coming with only three days’ notice. For most hospitals, the change is not expected to have any near-term effect, because they generally don’t rely on the state lab to process their tests, but some do, and others fear the loss of a backstop they could look to when capacity is stretched thin.

“We are evaluating this sudden news and how it will impact our operations,” said Dr. James Jarvis, physician incident commander for Northern Light Health. The nine-hospital network, which includes Eastern Maine Medical Center in Bangor and Mercy Hospital in Portland, draws on the state lab when the network’s clinical volume exceeds its own lab capacity.

“The state lab has been and continues to be an invaluable resource for our state,” Jarvis said.

Central Maine Healthcare, which operates hospitals in Rumford and Bridgton, as well as Lewiston’s Central Maine Medical Center, generally uses an out-of-state commercial lab, Quest Diagnostics, to process its tests, but sometimes has turned to the state lab when Quest has become overwhelmed by national testing demands, as happened this past summer.

“Having the state lab as a backup for us to be able to get results relatively quickly is important when you have someone you are trying to diagnose or when a team member may have been exposed,” said Dr. John Alexander, the network’s chief medical officer. “This takes one of our options away, and we need to plan around what to do about that.”

Jackie Farwell, spokesperson for DHHS, said via email that six hospitals rely on the state lab for the testing of most of their inpatients and outpatients: St. Mary’s Regional Medical Center in Lewiston, St. Joseph’s Hospital in Bangor, Downeast Community Hospital in Machias, Cary Medical Center in Caribou, Houlton Regional Hospital and MaineGeneral in Augusta, though the latter hospital said it only uses the lab for outpatients.

She said the state lab’s primary purpose is to respond to public health emergencies such as outbreaks, and that the changes are being made to ensure its ability to do so. She noted the state lab would support universal testing within a hospital in the event of an outbreak.

“We recognize that this change means several hospitals will need to explore their own labs or commercial labs as options for testing of their patients,” Farwell said.

St. Mary’s spokesman Stephen Costello said the hospital has been using the state lab primarily for testing pre-surgical patients and symptomatic or exposed employees. “Now that they are not available we will need to use a different lab,” he said via email. “There is equal service, but there will be added cost for us to do so.”

York Hospital processes its tests through a commercial lab, but its infectious disease specialist, Dr. Evangeline Thibodeau, said there could be secondary effects. “We are concerned this processing change may impact other commercial labs that we use as demand there will increase,” she said via email.

The state’s largest hospital network, MaineHealth, has a large laboratory of its own, NorDx, and spokesman John Porter said the change was not expected to have an impact on operations. The hospital network includes Maine Medical Center in Portland and Southern Maine Health Care Medical Center in Biddeford, among others.

MaineGeneral in Augusta relies on the state lab to process its primary and urgent care patients’ COVID-19 tests, spokesperson Joy McKenna said, but has arranged to switch over to Jackson Laboratory in Bar Harbor. Jackson already provides large-scale COVID-19 testing for the state of Connecticut at a facility there, and McKenna said MaineGeneral doesn’t anticipate a huge impact from the changeover.

Tuesday’s development followed Monday’s announcement that the Maine Center for Disease Control and Prevention would cut back its contact tracing and investigations by 40 to 60 percent in order to concentrate resources on the most vulnerable populations: children and the elderly; health care workers and first responders; people who are hospitalized, disabled, working or living in congregate care facilities; and those associated with schools or child care facilities.

The state saw a record single-day new case load Monday of 427 new cases, while the number of those hospitalized by the disease has hit record levels. On Tuesday the state reported another 274 cases and 12 deaths.