Medical Tests

When should I start getting mammograms?

DEAR DOCTOR K: I'm a 47-year-old woman who has never had a mammogram. Some experts recommend I get one, but others do not. I understand that the American Cancer Society recently updated its recommendations about breast cancer screening. Does it say I should have a mammogram? If so, which experts should I believe?

DEAR READER: I'm surprised when people are bothered by medical experts having different opinions. Expert politicians, expert lawyers, expert architects -- experts of all kinds disagree with each other all the time. Why? Because it is rare for the "truth" of any question to be clear beyond dispute.

What will happen during my pulmonary function tests?

DEAR DOCTOR K: My doctor ordered breathing tests to see if I have asthma. He didn't tell me what it's like to go through this. Can you explain?

DEAR READER: The tests your doctor almost surely is referring to are pulmonary function tests. The tests are painless. You breathe in and out through a tube that is connected to various machines.

Should I have my vitamin D level checked?

DEAR DOCTOR K: I've read several articles about the negative effects of a low blood level of vitamin D, but my doctor said I didn't need to have my level checked. Why not?

DEAR READER: Many of my patients are asking me the same question. Vitamin D has been in the news a lot in recent years, but we still don't have solid answers to many questions, including yours. There is strong evidence that people with a low blood level of vitamin D have higher rates of osteoporosis (thin bones).

Is the home-screening test for colon cancer effective?

DEAR DOCTOR K: I heard about a new home test that detects colon cancer. Is it a good alternative to colonoscopy?

DEAR READER: The new test appears to be an advance, but I don't think it's as good as colonoscopy. Particularly for people who are at higher risk for colon cancer, I regard colonoscopy as the best test. Colon (or colorectal) cancer lies in the wall of the colon. It can cause painless bleeding. The amount of blood can be so small ("occult blood") that it isn't visible in the bowel movement, but it can be detected by chemical tests.

Should I request advanced cholesterol testing?

DEAR DOCTOR K: Should I request "advanced" cholesterol testing at my next checkup?

DEAR READER: A standard cholesterol test, or lipid profile, measures levels of HDL, LDL, total cholesterol and triglycerides in the blood. So-called "advanced" cholesterol testing is a more detailed version of this test. Cholesterol is a waxy, yellowish fat. It travels through your bloodstream in tiny, protein-covered particles called lipoproteins. These particles contain cholesterol and triglycerides, a type of fat.

Why would a doctor order an ultrasound of the carotid artery?

DEAR DOCTOR K: My father's doctor wants him to have an ultrasound of his carotid artery. What is the carotid artery? What will the doctor be looking for?

DEAR READER: The carotid arteries carry oxygen- and nutrient-rich blood from the heart to the brain. These crucial arteries can become narrowed by the cholesterol-filled plaques of atherosclerosis. Blood clots can form from the plaques, then break off and travel to the brain. There, they can lodge in small arteries, interrupting the vital flow of blood to brain cells.

Will studies of our genes change medicine and improve our lives?

In yesterday's column, a reader asked whether she should be tested for genes linked to Alzheimer's disease. Today, I thought I'd give you my view on the larger question: Will studies of our genes change the practice of medicine and improve our lives?

My answer: During my career, progress in human genetics has been greater than virtually anyone imagined. However, human genetics also has turned out to be much more complicated than people imagined. As a result, we have not moved as rapidly as we had hoped in changing medical practice.

Why do I need a HbA1c test every few months for my Type 2 diabetes?

DEAR DOCTOR K: I have Type 2 diabetes, and I check my blood sugar levels every day. Why do I need to have my HbA1c levels tested every few months?

DEAR READER: Diabetes is marked by high levels of glucose (sugar) in the blood and urine. Without adequate treatment, diabetes can cause serious long-term complications. The key to preventing them is to control blood sugar -- to keep it close to the normal level.

Can you tell me what the different breast biopsy techniques involve?

DEAR DOCTOR K: My doctor saw something suspicious on my mammogram and wants to do a breast biopsy. I understand there are several biopsy techniques. Can you tell me what they involve?

DEAR READER: The invention of mammograms (X-rays of the breast) has saved many lives. Mammograms can spot a small, early breast cancer, and help doctors cure it.

Why is it complicated to test testosterone levels?

DEAR DOCTOR K: I've been having symptoms that may be caused by low testosterone. I figured it would be easy to test my testosterone levels, but my doctor says it's complicated. Why?

DEAR READER: Testosterone is one of the main male hormones. Blood levels of this hormone start to sag in early adulthood, and then creep lower. In some men, the levels become low enough to cause symptoms. The classic symptoms of low testosterone ("low T") are low sex drive, erectile dysfunction, poor muscle tone, poor concentration and memory, and low energy.