Four disease screening items

Hepatitis B virus surface antigen (HBsAg), hepatitis C virus antibody (anti-HCV), human immunodeficiency virus antigen and antibody combined test (anti-HIV, that is, AIDS screening), Treponema pallidum antibody (anti-TP). In a few contexts, the “four disease screening items” also refer to the four pre-pregnancy eugenics items, that is, screening for Toxoplasma gondii, rubella virus, cytomegalovirus, and herpes simplex virus. Let’s make this point clear first, don’t get confused.

If you go to the hospital to have your wisdom teeth extracted, a sebaceous cyst removed, or even for an ordinary gastroscopy, you will most likely see these four items on the bill. Many people will mutter when they get the bill: Am I just a small operation with no bleeding? Did the doctor prescribe random tests?

I also had this doubt when I first rotated to the general surgery department, until I met the young man who was doing inguinal hernia repair. He was 22 years old and had just graduated. He was usually in good physical condition and rarely even caught a cold. Before the operation, he was routinely found to be positive for syphilis antibodies, and the titer was not low. He had no symptoms at all, and he had latent syphilis. If this item was not checked, not only would no one know that emergency intervention was needed if the instrument scratched the medical staff during the operation, but he also did not know how long it would take for his own disease to be discovered. Later, he was transferred to the dermatology department for three weeks of long-acting penicillin. The titer of the reexamination dropped quickly, and there were no sequelae.

Of course, the industry does have different opinions on the screening indications for these four items. Many teachers from grassroots hospitals believe that as long as it is an invasive operation, no matter how big or small, it must be checked. Firstly, it is to prevent the patient from getting infected and cross-infection to other patients during the operation. Secondly, if the infection is discovered after the operation, it can also be clear whether it was preoperative or iatrogenic, so as to avoid unnecessary disputes. However, many experts in evidence-based medicine believe that it can be distinguished based on the risk level of the operation. For example, if it is just a small operation such as subcutaneous lipoma resection, which is almost non-bleeding, and the patient clearly has no high-risk history, there is no need for mandatory screening, which will waste medical resources and increase the financial burden of the patient. Both views are actually reasonable, and the implementation standards of hospitals in various places are indeed different.

Don’t be overwhelmed when you see a positive result. False positives are not uncommon. I met a pregnant mother who was 2 months pregnant in the outpatient clinic before. She was found to be positive for syphilis antibodies when she made the card. She sat in the clinic and cried for half an hour. She said that neither she nor her husband had high-risk behaviors, so the hospital must have made a mistake in the test. Later, she was prescribed a syphilis confirmatory test (TPPA) and a titer test, and the results were both negative. It was a false positive caused by hormonal changes in the body during pregnancy, and it was a false alarm. In addition to pregnant women, elderly people with autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis are also prone to false positive antibodies. If abnormalities are detected, further testing should be done first, and don't make blind assumptions.

If you have had high-risk behaviors before, you don’t have to wait for surgery to check these four items. Now community hospitals and CDC can check them. Most of them use rapid tests, which cost dozens of yuan and can produce results in half an hour. The effect of early detection and early intervention is really much worse. Take AIDS as an example. If there is a high-risk exposure, the success rate of taking blocking drugs within 72 hours can reach more than 95%. If you wait until you have symptoms before checking, it will be too late.

All in all, the reason why these four screenings have become routine clinical items for decades is that they are cost-effective enough, costing dozens of dollars each, to protect both patients and medical care. Of course, the future will definitely move in a more precise direction. Maybe in a few years, you won’t need to check these four items every time you perform small operations. But now, if the doctor prescribes it for you, don’t rush to resist it. If you really have any questions, just ask them directly. After all, when we see a doctor, don’t we just want peace of mind?