Glasgow GP Margaret McCartney said there is "confusion" about smear tests both among the public and the medical profession.
Writing in the British Medical Journal (BMJ) she said that recent high-profile campaigns to lower the age of cervical screening are "understandable".
But she said that it is "clear" that these cases presented to their doctors with symptoms of cervical cancer and the patients should have been referred for diagnostic tests, not smears. Cervical screening could have in fact delayed referral for diagnostic tests, she added.
At present, women in England, Wales and Northern Ireland aged 25 to 60 are offered cervical screening tests every three to five years. The ages vary slightly in Scotland but will be amended from next year to be in line with other parts of Britain.
Earlier this month MPs debated cervical cancer screening after more than 320,000 people signed an e-petition calling for the smear test to be offered to women aged 16 and above.
Dr McCartney wrote: "From the news reports available, it's clear that the women in recent high-profile cases presented to their doctors with symptoms of cancer. Screening wasn't what they needed. It would have only delayed referral for appropriate diagnostic tests.
"NHS guidelines recommend history-taking, examination, and swabs or referral to hospital for such young women with symptoms. Smear tests do not feature."
She said that screening and diagnostic tests are often confused among the media, the health profession and the general public.
And campaigns to lower the age of screening would "leave a useless legacy", she wrote.
"These campaigns may do more harm than good because they haven't understood who screening is for," she said.