Amy Winehouse is to undergo further tests to determine if she has contracted tuberculosis, according to a tabloid report.

The singer has been at a private clinic in London since Monday when she collapsed at her Camden home.

Whilst tests to determine the cause of the fainting episode are said to proved inconclusive, doctors apparently fear that her symptoms – allegedly a irregular heartbeat and a chest infection - could be a sign that she is suffering from the potentially deadly disease.

"Amy is in a bad way. Doctors are still struggling to control her heartbeat but the chest condition has been really worrying them," a source tells The Sun.

"She'd been suffering horrible coughing fits and hurling up blood for a while but refused to be examined.

"Doctors now believe it is tuberculosis and are doing more tests to be certain."

The infectious condition is said to be common among drug addicts and heavy drinkers, as they have a reduced immunity and are more vulnerable to infection.