A woman factory worker lodged a complaint with police yesterday over suspicions her right kidney had been stolen during surgery to remove an ovarian cyst two years ago.

Gasorn Pumchang, 43, who works in a factory in Samut Prakan, said she only found out about the missing kidney when she had a health check-up to find out what had been causing her to faint and suffer pains in her waist and leg.

She had frequently been absent from work because of ill health since the operation, she said.

Her doctor discovered Mrs Gasorn does not have a right kidney, while her left kidney is functioning at only 40%. She has been diagnosed as being at risk of kidney failure.

Mrs Gasorn said an X-ray at another hospital after a car accident in 2005 showed she had both kidneys then.

Deputy national police chief Jongrak Juthanont said the woman suspected her kidney was taken without her knowledge when she had an operation to remove a cyst from her right ovary at a private hospital in Bangkok's Thonburi area in 2006.

Pol Gen Jongrak said kidney removals must be done by a skilled surgeon.

Deputy Public Health Minister Wicharn Meenchainant instructed the Medical Registration Division to look into the case by tracking the woman's medical records at both hospitals.

Division director Thara Chinagarn said Mrs Gasorn would be asked to undergo a CT scan to check her kidneys.

Mr Wicharn said there were several reasons why a kidney might appear to be missing, such as it not being present since birth, it being in an abnormal position in the body, or having been removed after an accident.

Pol Gen Jongrak said a kidney thief could be charged with assault causing grievous bodily harm, an offence with a prison term of six months to 10 years.

Also, because a kidney is regarded as personal property, the culprit would at the same time be charged with robbery and face a maximum three-year jail term and 6,000-baht fine.