CHARLESTON — West Virginia may stop short of expanding Medicaid as much as the federal health care law calls for, according to a Thursday letter from Gov. Earl Ray Tomblin.

Tomblin wrote U.S. Health and Human Services Secretary Kathleen Sebelius asking how much federal aid would flow to West Virginia if the state opts not to offer Medicaid to people with unadjusted annual household incomes of up to 138 percent of the federal poverty level. That’s a far higher income level than the state currently allows, and for a family of four is around $31,800.

The federal overhaul calls for states to expand Medicaid to that level in 2014. When the U.S. Supreme Court upheld the law last month, the 5-4 ruling also said the federal government could not take away a state’s existing federal Medicaid dollars if it refused to widen eligibility.

Federal funds would cover the states’ costs of expanding Medicaid, but only for a few years. Among other questions in Tomblin’s letter: Could West Virginia receive that enhanced funding if it expands Medicaid eligibility to some income level below 138 percent of the federal poverty level? Could the state expand Medicaid to a 100 percent poverty threshold, or $23,050 for a family of four, and then offer federal subsidies and tax credits to help those between 100 percent and 138 percent buy private insurance?

Tomblin’s letter also inquires about expanding Medicaid to the higher level, but gradually. However, the letter makes clear as well that the state has yet to choose how to proceed.

“Before a final decision is made, West Virginia must have a plan for the long-term sustainability of any type of Medicaid expansion,” Tomblin said in a statement Thursday. “Right now, we don’t have the information necessary to make the decision.”

An estimated 130,000 West Virginians would gain coverage if the state heeds the federal law’s expansion call. Tomblin noted in his letter that the state ranks high for such chronic health ailments as hypertension, diabetes, heart disease and obesity. Increased access to doctors can help people combat these conditions while offering them check-ups and other alternatives to costly emergency room visits.

“This, in turn, has the potential to reduce health care costs in the long run, saving taxpayer dollars and keeping insurance premiums and copays lower,” Tomblin wrote. “The healthier we are as a state, the more productive we can be from an economic perspective.”

But much of the letter cites the growing burden of Medicaid on the state budget, even without the called-for expansion. The program has become the biggest reason behind general revenue spending increases.

“We take our balanced budget responsibility seriously, and health care funding competes with other significant state priorities including education, public safety, infrastructure, economic development and environmental protection, among others,” the letter said.

Perry Bryant is executive director of West Virginians for Affordable Health Care, a coalition of labor, social service and other groups that strongly support the federal law. Bryant said budgetary concerns dominate the governor’s letter, with the potential benefits appearing as a secondary concern.

“It’s clear that he put being fiscally responsible as a core function,” Bryant said Thursday. He added, “Being uninsured is more than an inconvenience. Studies show that four West Virginians will die this week because they lack health insurance. Four more will die next week, and so on ... You don’t get that sense from reading the letter.”

About 244,000 West Virginians — or about 13.5 percent of the population — are currently uninsured. And while the state ranks 12th for the relative size of its Medicaid population, with 330,000 enrolled, it has among the strictest standards for qualifying.

A single parent with one child, for example, must earn less than $5,300 a year — 35 percent of the poverty level. Working-age adults without children can’t enroll even if they lack any income, unless they’re blind or disabled. More enrollees are people with those disabilities or children.

Tomblin’s letter also asks about the overhaul’s call for health care exchanges. These state-by-state marketplaces would aim to pool the buying power of individuals and small businesses as they seek health coverage from private insurers. Bryant said some of the answers won’t likely be available soon, such as updated rules for carrying out that provision that reflect the Supreme Court ruling. But others are imminent, such as details regarding benefits deemed essential for plans offered in exchanges, he said.

The letter also requests guidance about how states approach individuals who face penalties for not buying insurance. A key finding of the Supreme Court decision upheld that individual mandate under the power of Congress to levy taxes.