NEW YORK (AP) – New DNA technology developed by a Virginia laboratory to help identify years-old remains of Sept. 11 victims is working for all but the smallest slivers of bones, a scientist says.

But identifying a Sept. 11 victim still takes weeks of painstaking review and often depends on factors like the quality of DNA samples originally provided by families from items like toothbrushes, a city spokeswoman said Saturday.

“The last thing we want to do is submit an ID to someone and have it not turn out to be an ID,” said Ellen Borakove, spokeswoman for the city medical examiner’s office.

The city announced earlier this week that remains of five victims, including a city firefighter, had been identified. But more than 1,100 victims still do not have identifiable remains.

Last fall, Chief Medical Examiner Dr. Charles Hirsch told victims’ families that a new procedure for extracting DNA from remains would likely lead to new identifications.

That procedure, which extracts calcium from bone over a period of about a week, has yielded purer DNA samples than previous tests of bones badly damaged by extreme heat and time, said Mike Cariola, vice president for forensic operations at Lorton, Va.-based Bode Technology Group.

“The procedure works for the remains that we test” with the exception of the tiniest of bone fragments, weighing 100 milligrams or less, he said. “I don’t think there’s any DNA to be found in these, they’re so small.”

Mr. Cariola said two to five scientists at the lab work full time creating DNA profiles to send to the city to find possible matches. He declined to say how many profiles the lab had successfully delivered or how many bones were too small to be identified, saying the city had requested that information not be released.

Ms. Borakove said that a strong DNA profile “does not equal a new identification.” She said a few dozen newly identified fragments turned out to be matched to previously identified victims; and in some cases, the city does not have samples of victims’ DNA to link to remains.

Two forensic biologists, one part-time staffer and three anthropologists ultimately conduct a series of reviews to check the quality of the DNA profile provided by the Bode lab against the samples the city maintains, Borakove said.

Ms. Borakove said she could not say how many remains the city has examined again since last fall. More than 10,000 remains have been recovered in all, including more than 1,200 found in the past 18 months in and around the World Trade Center site.

Family members say recent identifications have brought both hope and anxiety. Charles Wolf, whose wife’s remains were never recovered after she died in the trade center, prefers not to dwell on the unknown.

“I just go on living,” he said. “Until someone calls and say we found something of Katherine’s, I don’t want to think about it. … I’m not interested in setting myself up for anticipation.”