The plan calls for a corporation to build and run a state-of-the-art lab facility under a public-private partnership.
Liberals and New Democrats say privatizing such a key part of the health system will not benefit Albertans.
NDP health critic Dave Eggen says pathologists have raised concerns about how a private lab might affect patient safety and quality of care.
The Alberta Union of Provincial Employees also opposes the plan.
Alberta Health Services says it wants competitive bids before the end of March, and promises no workers will lose their jobs under the plan.
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