(MONEY Magazine) – Call me a convert. After receiving a wicked Stage 3 colon cancer diagnosis four years ago at age 43, I've changed my thinking about Big Medicine and high-tech diagnostic scans. Bring 'em on--early and often. I was in a high-risk pool, so I started screening early, at 40; but looking back, I would have been better off had I started even earlier. One reason I'm here is that a high-resolution CT scan gave my surgeons and oncologists invaluable insight into how to proceed. I hasten to add that their great skill in reading that scan was as vital to my survival as was the technology that produced it. I am also, I should note, properly skeptical. After 20 years of medical reporting, I've learned that not every "breakthrough" test actually is. There are often three sides to the story: the exciting news, the limitations and the likelihood that the ultimate answer is still a long way off. Having said that, here are five areas where many doctors, and certainly I, part company with conventional medical and insurance wisdom. I believe it pays to spend your own money on these tests to get the most complete information.

C-REACTIVE PROTEIN (CRP) BLOOD TEST $60 The CRP Blood Test, one of the biggest advances in cardiovascular health this decade, reveals subtle inflammations in the veins, heart or other areas. Dr. Paul Ridker of Brigham and Women's Hospital in Boston says patients who have both CRP and cholesterol measured get a more accurate reading of heart risk than they would from cholesterol tests alone. He has found that high CRP levels point to a markedly elevated risk for heart attack or stroke, even in individuals with safe cholesterol levels. Other researchers say CRP may soon help doctors identify many diseases in their formative stages, including the abnormal cell growth that typically precedes a diagnosis of cancer.

PILLCAM VIDEO FOR DIGESTIVE DISEASE $500 TO $2,000 The Pillcam is a tiny camera and strobe light inside a vitamin-size pill casing. You swallow it while wearing a receiver in a waist pack. It takes digital images of parts of your digestive tract, and later you simply flush it away. "The videos are excellent," says Dr. Glenn Eisen of Oregon Health and Science University, one of the country's leading Pillcam centers. The device can hunt for polyps and other growths, Crohn's disease, severe acid reflux or Barrett's esophagus, a condition that presages esophageal cancer. The cost is high, but insurance plans are beginning to cover the test if a doctor has ordered it to diagnose unexplained bleeding or inflammation.

SEX-HORMONE ASSESSMENT $150 TO $1,500 Declines in Testosterone, Estrogen, DHEA and HGH (human growth hormone) are associated with accelerated aging. A workup can quickly tell women as well as men how their hormones are holding up. Despite new forms of delivery, such as testosterone patches and gels, there are concerns about the possible links between higher levels of sex hormones and cancer, particularly of the prostate and breast. It's not that supplements necessarily cause cancer, but they may accelerate the growth of an undetected tumor.

DHEA is a precursor to estrogen and testosterone. Many experts consider it safer to take than synthetic sex hormones, as long as a doctor monitors the case.

CEA AND CA125 BLOOD TESTS $90 TO $100 The CEA (carcinoembryonic antigen) and CA125 (cancer antigen) tests are designed to spot early signs of cancer recurrence. They're not useful as broad-based screening tools, according to the American Society of Clinical Oncology, because they work only in people who have had cancer. Also, they tend to produce high rates of false positives (especially among smokers). Nonetheless, they represent an exciting advance. The tests hunt for the presence of cancerous or precancerous cells in the thyroid and digestive tract (CEA) and in the female reproductive system (CA125). After the first test gives patients a baseline score, successive tests serve as a sensitive early-warning system.

GENETIC COUNSELING $300 TO $3,000 Used to be, family medical histories were taken with paper and pen and relied heavily on recollection. An interview is still part of the process, but today's genetic counseling, offered at most teaching and cancer hospitals across the country, can go much further. Your blood sample can be analyzed for the presence of genetic markers indicating a predisposition to various diseases or conditions. These include the "breast cancer genes" BRCA-1 and BRCA-2 as well as genes linked to Tay-Sachs disease, sickle-cell anemia and other cancers. Heart attacks may soon join the list--researchers have identified many genetic variations associated with increased cardio risk.