It also accounts for 90 percent of all healthcare related contracts, which researchers Everest Group expect to more than double to about $68 billion (roughly Rs. 4,32,029 crores) in 2020 from nearly $31 billion (roughly Rs. 1,96,954 crores) two years ago, largely due to "Obamacare".
"In terms of technology maturity, other sectors like manufacturing, banking, are a lot more mature than healthcare," said Rajib Bhattacharya, head of a healthcare software unit that India's fifth largest outsourcing firm Tech Mahindra Ltd set up last month.
"I think it's a huge opportunity," he recently told Reuters.
Average revenue growth for India's top five outsourcing firms by market value is expected to slow to 13.3 percent year-on-year in the quarter that ended June 30 from 18.6 percent growth in the same year-ago period, Thomson Reuters data shows.
The slowdown is largely due to banks, manufacturers and financial firms cutting down on IT spending amid uncertain prospects for the global economy.
By contrast, U.S. states have to upgrade healthcare programs and build online exchanges where buyers can evaluate and select service providers under Obamacare, creating outsourcing opportunities worth hundreds of millions of dollars.
Health care deals currently account for less than 10 percent of the sales of market leader TCS, which will be the first outsourcing firm to report first-quarter earnings on Thursday.
Last year, its annual revenue growth shrank to 13.6 percent from almost 30 percent growth in the previous year, the Reuters data shows. Rival Infosys also reported slower annual revenue growth of 6.9 percent from 24.2 percent in 2013/14.
Both TCS and Infosys declined to comment ahead of their quarterly results.
Researchers Gartner estimate global IT spending will this year fall 5.5 percent from a year ago to $3.5 trillion, which means competition for booming sectors like healthcare will be fierce.
Analysts, however, say Indian outsourcing firms must address U.S. concerns about privacy, and spell out how they intend to protect sensitive medical and personal data for U.S. patients that will be processed half a world away in India.
"The best chance that Indian companies will have is to make acquisitions of companies that specialize in healthcare technologies," said Kevin Parikh, chief executive of U.S.-based management consulting firm Avasant.
© Thomson Reuters 2015