You can probably recite most (if not all) of your personal health numbers—your body weight, cholesterol level, blood pressure and blood glucose—off the top of your head. You commit these metrics to memory because they provide at-a-glance insights into your cardiovascular and overall health.

Something else you need to know: There are other important numbers that tend to get overlooked. Staying on top of them will help you more accurately apprise your health status…and can motivate you to make personal changes that could very well save your life. Also: Be sure to always ask your doctor for copies of your blood test results so that you can keep your own record of your numbers.

Four key health numbers to know—with appropriate coding, insurance should cover the cost of these tests, but check first if you have questions…* 

1. Alanine transaminase (ALT)

A routine physical exam usually includes a blood test to measure levels of a liver enzyme known as ALT. Keep tabs on this number because high (or rising) levels can indicate non-alcoholic fatty liver disease (NAFLD), a condition in which excess fat is stored in the liver. 

This disease usually causes no symptoms in the early stages, so you won’t know that you have it unless you get tested. NAFLD is serious business—it’s a major cause of liver cirrhosis, liver cancer and liver transplants. And it affects 30% to 40% of US adults. 

What to do: This test is usually part of a routine physical, but the result may be passed over. Keep an eye on it!

Optimal ALT level: Approximately 7 U/L to 56 U/L (aim for the lower end of the reference range your lab uses). Exception: People with risk factors for NAFLD, such as obesity, metabolic syndrome (a cluster of conditions including high blood pressure, elevated blood sugar and belly fat) or type 2 diabetes, may have the disease even when the test results are in the upper half of the normal range. Your doctor might recommend additional tests, such as an ultrasound of the liver, if he/she suspects NAFLD. 

If you test high: If you’re overweight and catch the disease early, losing just 10% of your waist circumference (or your total weight) will usually help the liver return to normal. If you’re in the early stages of NAFLD, lowering cholesterol and triglyceride levels also helps. 

2. Glomerular filtration rate (GFR)

This is the most useful blood test for detecting kidney disease.

What to do: Get the GFR test every year. It measures the filtering capacity of the kidneys. Testing is critical because you can lose up to 75% of kidney function before you develop symptoms (such as frequent urination and/or swelling of the feet or ankles). Diabetes and high blood pressure are the main risk factors for kidney disease. Smoking, high cholesterol and obesity also increase your risk.

Optimal GFR level: Ideally, 90 or above. Below 60 for three consecutive months indicates chronic kidney disease, and 60 to 89 can be normal based on a person’s age…or indicate stage 2 kidney disease. A higher number is better because it indicates how efficiently the kidneys filter toxins from the blood.

If you test low: Talk to your doctor about lifestyle changes that support kidney health—regular exercise, a healthy body weight, not smoking and a diet that includes potassium-rich foods such as fruits and vegetables (if you already have some loss of kidney function, you may need to restrict potassium). Your doctor also may recommend an ACE inhibitor, such as enalapril (Vasotec), or a calcium channel blocker, such as diltiazem (Cardizem), to lower blood pressure. Because the kidneys are a complex vascular system, the odds of wear and tear increase significantly in the presence of elevated blood pressure. 

3. LDL-P

A standard cholesterol test is fine for those with average cardiovascular risk, but you may need a more specialized test if you’ve been diagnosed with heart disease…have a family history of early heart attack or stroke (before age 55 for men and age 65 for women) in a first-degree relative (a parent or sibling)…or are at high risk due to metabolic syndrome. 

The traditional test for LDL “bad” cholesterol measures the amount of cholesterol that’s present in blood. LDL-P is an advanced lipid test that calculates the number of LDL particles themselves. The distinction is important because the particle number is directly linked to disease, even in patients with normal cholesterol readings. 

What to do: If you have—or are at increased risk for—cardiovascular disease, ask about an NMR Lipoprofile, which includes an LDL-P test.

Optimal LDL-P level: Below 1,000 nmol/L.

If you test high: Genetics can contribute to high LDL-P, but people who exercise, eat well and manage their weight—and, in some cases, take a statin and/or aspirin—can lower their cardiovascular risks to close to normal.

4. Abdominal Circumference

This isn’t a blood test, but it’s a crucial number because a person can have a normal body weight but a large midsection.

What to do: Use a tape measure to measure your midsection—without clothing, one inch above your navel. People with larger–than-expected bellies (as well as those who are both obese and “apple shaped”) have a higher risk for heart disease than those with slimmer middles. 

The internal fat that causes waistlines to expand, known as visceral fat, releases hormones, inflammatory chemicals and other compounds that increase risk for chronic disease. Excess belly fat in men is also linked to erectile dysfunction. 

Optimal abdominal circumference: The US standard is less than 40 inches in men…and less than 35 inches in women. But I advise my patients to aim for the International Diabetes Foundation’s target of less than 37 inches in men…and less than 32 inches in women.

If you measure high: Try to reduce your abdominal measurement by 10%. Regular exercise (including strength training) and healthful eating will help. 

* Normal ranges may vary slightly depending on the lab. In addition, factors such as age, sex and race can influence what’s normal. Ask your doctor to explain all of your tests.