Is it normal for disease screening tests to be negative?

In most cases, the results are completely normal, which means that among the diseases covered by this screening, you have no abnormal indicators that meet the clinical diagnostic standards for the time being. It is absolutely okay to breathe a sigh of relief after receiving this kind of report.

However, clinically we never equate "screening all negative" with "nothing wrong with the body", and the reason is not difficult to understand. When I was rotating in the respiratory department, I met an old patient who had smoked for 40 years. Every year during the work unit physical examination, the chest X-ray screen for lung cancer was negative. He coughed for two months that winter and still had bloodshot eyes. Even after taking a chest X-ray, no problem was found. Finally, a thin-section CT of the chest was performed and it was discovered that there was an early-stage adenocarcinoma less than 1 cm hidden in the upper lobe of the right lung. The position was blocked by the ribs and could not be photographed at all on the chest X-ray.

In fact, the screening items we often do have their own limitations, a bit like using fishing nets with different meshes to catch fish. Naturally, larger meshes cannot catch small fish. The sensitivity of some items is inherently limited, such as conventional tumor markers. They can only be detected when the tumor develops to a certain scale and secretes enough related substances. Early lesions can easily be missed.； There is also a "window period" for screening for infectious diseases such as AIDS and hepatitis B. Even if there are pathogens in the body in the first few weeks of infection, the reagent cannot detect them. The negative results at this time are actually false negatives.

Now the industry has different views on this matter. Many general practitioners believe that if you have no discomfort, no family history of related diseases, and no history of high-risk exposure, routine screening of the entire vagina does not require additional examinations, so as to avoid excessive medical treatment and tormenting people.； However, many specialists will repeatedly remind high-risk groups, such as those who smoke all year round, have a family history of breast/ovarian cancer, and have long-term exposure to dust or radioactive substances, that they should not just look at the negative results of routine screenings, but should conduct targeted and precise screenings regularly.

Two months ago, a 28-year-old girl came to the outpatient clinic, and her annual gynecological examination was all negative. It was because both her grandmother and mother had ovarian cancer. She followed the advice of a specialist and did a pelvic MRI and BRCA gene test. Only then was she discovered a very early junctional ovarian lesion, and she underwent minimally invasive surgery in time, which basically did not affect her subsequent life.

In fact, to put it bluntly, our screening is a matter of "casting a wide net to find risks". Of course, being completely negative is a good thing, but it is not a "gold medal". If you really have persistent discomfort, such as inexplicable stomach pain, sudden weight loss, and long-term cough, don't rely on the negative screening report. It is most reliable to see a doctor for targeted screening.