Your nails can tell you much more than whether you need a manicure. They’re packed with details about your health. They can show if you have an infection, a serious disease, or even how well you’re eating.

To figure out what your nails might have to say, answer these questions. If you’re concerned, ask your doctor, as you’ll need more than a glance at your hands to know if there’s a problem.

1. Do they look pale or white?

This could mean you have a low red blood cell count. White nails also can signal liver disease, diabetes, an overactive thyroid, heart failure, or a lack of nutrients in your diet.

If your nails are mostly white with a narrow pink band at the tip, you have a condition called Terry’s nails. It can result from aging, but it can also herald diabetes or kidney, liver, or heart disease.

2. Are they yellow?

Nails that are thick, slow-growing, and yellow often point to lung diseases like emphysema or chronic bronchitis. Fluid in your lungs and hands also can lead to yellow nail syndrome. So can Raynaud’s phenomenon, which is caused by poor circulation to the fingers, toes, and nose. Yellow nails can even be a symptom of sinusitis, thyroid problems, lymph accumulation, and rheumatoid arthritis. Occasionally, yellow nails run in families, suggesting a genetic connection. Only your doctor can tell you what they mean.

3. Are your nail beds red?

Talk to your doctor. She’ll probably want to examine your heart.

4. Do they look a bit blue or purple (without any nail polish)?

Your doctor may call this cyanosis, which is a medical word for that skin that looks that way. You might notice it on other parts of your body, too, such as your lips or even your earlobes. It can happen if your red blood cells aren’t carrying enough oxygen. Your doctor will see if your heart, lungs, blood cells, and blood vessels are working right.

5. Do you see thin red or brown lines?