By Sharon Begley and Lewis Krauskopf NEW YORK (Reuters) - U.S. medical providers are seeing only a trickle of patients newly insured under President Barack Obama's healthcare law, as insurers, hospitals and doctors try to work out any hitches in coverage. More than 2 million people have signed up for new private health plans that took effect on Wednesday under the Affordable Care Act, popularly known as Obamacare. Already on Friday, Senate Republicans opposed to the law seized on scattered media reports of a handful of people having difficulty confirming their new insurance policies, feeding into a narrative of Obamacare's harms that is expected to intensify ahead of Congressional elections in November. Central Ohio Primary Care, a 250-physician practice, is holding off on filing claims for patients who say they bought plans through the HealthCare.gov exchange, said Chief Executive Officer Dr. William Wulf. read more..