Thailand's 83-year-old Queen Sirikit has undergone medical tests and has "insufficient blood in the brain", the Royal Household Bureau has said in a rare statement on her health.
Her husband, King Bhumibol Adulyadej, 88, is in failing health and is also being treated for various ailments at a Bangkok hospital.
The Thai royal succession has prompted worries about instability in a country that has witnessed 19 coups or attempted coups and at least 19 constitutions since a constitutional monarchy replaced an absolute one in 1932.
"An x-ray showed that there is still a trace of a former illness of insufficient blood in the brain as per in 2012 but the check found no new abnormalities," the palace said on Friday.
In a second statement late in the day, the palace said Queen Sirikit's medical tests were completed and yielded "satisfactory results".
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Queen Sirikit, who has seldom been seen in public in recent years, went for a health check on Wednesday, it said.
The palace last released a statement on Queen Sirikit's health in 2014.
