A colonoscopy costs $1,730 for an uninsured patient having the procedure done at Penobscot Bay Medical Center in Rockport.

The same patient would pay as little as $1,130 for a colonoscopy at Mercy Hospital in Portland or as much as $4,895 at the Charles A. Dean Memorial Hospital in Greenville.

These are among the findings of a cost comparison provided by the Maine Health Data Organization. The organization was created by the Legislature in 1996 to make clinical and financial health care information available to the public.

The cost comparison maintained by the organization is based on data through Dec. 27, 2007.

The organization provides cost comparisons on several common medical procedures. The Maine Health Data Organization said that hospitals provide free care for people earning less than 150 percent of the federal poverty level and some provide free care for people earning as much as 200 percent of the federal poverty level. Hospitals also offer sliding scale payments based on income and payment plans.

The current federal poverty rate is $10,830 for a single person, $14,750 for a two-member family and $18,310 for a family of three. The level increases until it reaches a family of eight or greater with the poverty level set at $37,010 for a family of that size.

Al Prysunka, executive director of the Maine Health Data Organization, said there is a tendency for the costs to be less at larger hospitals because of the high number of procedures done at those medical facilities.

For colonoscopies, the statewide average charge was $1,974. Penobscot Bay Medical Center’s median charge for the procedure was less than that at $1,730. At Waldo County General Hospital in Belfast, the median charge was $1,557 while at Miles Memorial Hospital in Damariscotta the median charge was $2,970 — the third highest charge in Maine. At Maine Medical Center in Portland, the charge was $1,326, the second lowest in Maine.

Third-party payers such as private insurance companies negotiate discounts with hospitals and Mainecare and Medicare impose limits on what they will pay to hospitals. For instance, the Rockport hospital received $1,084 from Anthem Blue Cross and Blue Shield’s preferred provider organization customers for a colonoscopy that costs a person with no insurance $1,730. Medicare pays $823 to Penobscot Bay Medical Center for the same procedure.

For a mammogram, the statewide average charge was $221 for an uninsured person. At Pen Bay Women’s Imaging in Rockport, the median charge was $167. The median charge at Waldo County General Hospital was $192. The median charge at Miles Memorial Hospital was $232.

The charges ranged statewide from $125 at Central Maine Imaging in Lewiston to $350 at Mount Desert Island Hospital. At Maine Medical Center, the charge was $192.

The median charge for a tonsillectomy in Maine hospitals was $4,663. At Penobscot Bay Medical Center, that price for an uninsured patient was $5,630. At Waldo County General Hospital, the cost was $5,721. Figures for Miles Memorial Hospital were not available.

Statewide the charge ranged from $2,763 at Maine Medical Center to $8,396 at Maine Coast Memorial Hospital in Ellsworth.

For arthroscopic knee surgery, the statewide median charge was $7,219. At Penobscot Bay Medical Center, the median charge for the surgery was $10,134. At Waldo County General Hospital, the median charge was $8,224. At Miles Memorial Hospital, the median charge was the most in the state at $12,924.

The charges statewide ranged from $4,675 at Maine Medical Center to the $12,924 at Miles Memorial Hospital.

The median statewide charge for having a gallbladder removed was $11,106. At Penobscot Bay Medical Center, the median charge was $10,813. Medicare’s payment to that hospital for a gallbladder removal was $3,851.

At Waldo County General Hospital, the charge was $12,747 and at Miles Memorial Hospital the charge was the highest in the state at $17,912.

Statewide, charges ranged from $7,663 at Maine Medical Center to the $17,912 at Miles Memorial Hospital.