(AP) SINGAPORE - Natalie Gulbis underwent blood tests Saturday after withdrawing from the HSBC Women’s Champions with an unspecified illness her instructor initially suspected could be malaria.

Gulbis pulled out of the $1.4 million event before the second round on Friday with flu-like symptoms. Shortly afterward, her instructor, Bruce Harmon, tweeted that both she and South Korean golfer Se Ri Pak, who withdrew from the tournament before it began with an illness, were in the hospital with malaria.

LPGA spokesperson Kelly Thesier said Saturday, however, that Pak does not have malaria and Gulbis has yet to be diagnosed. She said Gulbis has undergone blood tests but has not been hospitalized.

Gulbis shot an opening-round 75 on Thursday before withdrawing.