He was responding in Parliament after Dr Lim Wee Kiak, Member of Parliament (MP) for Sembawang GRC, asked if there were guidelines for doctors to "send all (patients) for detailed diagnostic test to avoid misdiagnosing rare medical conditions".
Dr Lim was citing the recent case of Dr Chia Foong Lin, who was suspended for three months, for not diagnosing a child who had the relatively rare Kawasaki disease (KD).
Dr Chia, who is in private practice, had appealed against the disciplinary tribunal's judgement previously, but the Supreme court upheld it.
More than 1,000 doctors subsequently signed a petition to the ministry and the Singapore Medical Council (SMC), saying that the punishment was too severe for misdiagnosing a rare disease.
Standard practice guidelines on diagnosis for rare diseases is "impossible"
Other MPs also posed similar questions as Dr Lim, regarding the case. Dr Lim then asked if the Ministry of Health (MOH) could issue standard practice guidelines on the diagnosis for rare diseases. He said that doing this would "neither (be) possible nor practical".
"Doctors would have to exercise their clinical judgment in such situations," he lamented.
Referring specifically to Dr Chia's case, there are already international guidelines on what calls for further investigations to diagnose the Kawasaki disease since 2004, citing symptoms such as persistent fever, red eyes, cracked lips and a rash.
The one-year-old boy in discussion had fever and three other symptoms: red eyes, a rash, and lips that were red and cracked.
The tribunal found that "Dr Chia fell short of the reasonable standard expected of a senior paediatrician by not ordering tests to support the diagnosis or discussing with the parents this possible diagnosis which she had considered," added Dr Lam.
This warranted her actions as "serious negligence", he emphasised.
Ms Tin Pei Ling, MP for MacPherson, then asked about the basis for Dr Chia's suspension.
Dr Lam replied that in deciding on the three-month suspension, the tribunal took into account her 23 years of experience as a paediatrician, and her unblemished record. It also looked at eight precedents of doctors missing or providing a wrong diagnosis. Six were suspended.
No local studies on defensive medicine yet
Ms Tin asked whether studies had been done on defensive medicine and potential implications if it was practised here, in response to Dr Lam's advice on practising defensive medicine.
Dr Lam said that there is no such local study, but many international studies ̶ mainly comprising surveys of doctors ̶ have noted the high prevalence of defensive-medicine practices overseas, resulting in unnecessary increases in healthcare costs.
"Other international studies have also suggested that a substantial fraction of malpractice claims are a result of a failure (in) doctor-patient communication," he added.
He also advised that doctors need to keep abreast of medical knowledge and international guidelines, which is why the SMC requires all doctors to have mandatory continuing medical education.
He also said that he was aware the case has caused concern among many doctors and urged them "to stay calm and not overreact", as well as to read the tribunal's rationale for the penalty. MIMS
9 of 10 Kawasaki disease patients at KKH under five years old
1,000 doctors call for dismissal of paediatrician's three-month suspension
Singaporean paediatrician suspended for three months due to misdiagnosis