Does cutting out wheat from your diet help your heart? Don’t forget the need to look at the big picture when evaluating lipid panel results. That's not only because the individual numbers aren't necessarily indicative of heart disease but also because they can vary quite dramatically.

The lipid panel doesn't actually measure the LDL number at all; rather, it estimates it with an equation using the total cholesterol, HDL, and triglyceride measurements. This point is important because it means LDL is dependent on the others that are directly measured. For instance, LDL will fall if HDL rises, and vice versa. Another problem is that if your triglycerides are under 100, your LDLs will be overestimated.

Your cholesterol levels change at different times of the day and from season to season. For example, total cholesterol levels generally go up in the winter and down in the summer. Just like you can't determine overall traffic patterns on the freeway by monitoring them only at one time of day, week, or year, you can't get a complete sense of your cholesterol situation based on one isolated lipid panel.

One of the reasons cholesterol levels fluctuate is that cholesterol provides healing in the body. When the body's stressed from, say, an infection or a medical treatment, it produces cholesterol and sends it to the area where the damage occurred.

When the wound heals, the body removes the cholesterol from the blood because it's unneeded, and cholesterol levels go back down. That's why people with chronic infections or inflammation have chronically high levels of cholesterol.

So how big a fluctuation is it really? Research has shown that the differences can be as high as 20 percent in either direction! For example, if your total cholesterol comes back at 220 one week, it may report at 264 or 176 the next week.

That wide range makes it hard for the doctor to interpret the results; he doesn't have an average but rather a snapshot in time. With a 264 cholesterol reading, most doctors would be very concerned and probably recommend a drug to bring the number down, while a 176 would likely get you a pat on the back.

These two drastically different scenarios, though they're extremes, help illustrate why a single reading isn't necessarily an accurate picture.

As an example, here is a true story with lipid panels. A patient was having two separate markers checked that required blood samples to be sent to different labs. The nurse drew two vials of blood, one right after the other, and sent each vial to a lab for analysis. As a courtesy, each lab also performed a basic lipid panel.

Guess what? The numbers were completely different. The patient’s total cholesterol differed by 11 percent, my LDL differed by 14 percent, my HDL differed by 6 percent, and my triglycerides differed by a whopping 84 percent! This was all the more reason not to trust one single test for diagnoses. A doctor may have decided to put this person on statins based on the results from one lab or send her on her way with a “healthy as a horse stamp” based on the results from the other lab.

The reality is that most people don't go to the doctor to get a lipid panel taken very often. At most, it's probably once a year during an annual checkup; every few years is likely more common. Think of ongoing monitoring of your cholesterol numbers as getting a second opinion on the results from a single panel.

After all, if you were diagnosed with cancer, you'd certainly get a second opinion; why not take the same approach to cholesterol and heart disease?