Health A-Z Medical Reference

Your body needs to have the right amount of the mineral potassium so that your nerves, muscles, cells, and heart are working well. Your doctor may order a blood test to make sure your potassium in the right range.

Learn which conditions your sedimentation rate helps your doctor diagnose. Also, find out how the test can guide your treatment.

Valley fever’s symptoms start out much like those of the flu. But this illness comes from a fungus that lives in the soil, and a few cases are serious.

How do you tell if your body is making enough red blood cells? That’s where a reticulocyte count test comes in. Learn more about how it works and why it’s important.

Experiencing swollen legs and foamy urine? It might be nephrotic syndrome. Learn more about the symptoms, causes, and treatments of this medical condition at WebMD.

If you have dehydration or an electrolyte imbalance in your blood, you may need an osmolality serum test. Learn more about how this test works.

Do you bite your nails? Find out what might be causing this bad habit and how to break it.

A partial thromboplastin time test tells you how long it takes your blood to clot. Learn what it looks for, when you might need one, and what the results mean.

If your calcium levels are too high or too low, you may need a parathyroid hormone blood test to learn why. Tiny parathyroid glands in your neck may be making too much or too little hormone to balance the calcium levels in your blood.

Your doctor might want you to get a luteinizing hormone test to check your fertility or check for a pituitary gland problem

Find out more about this genetic disorder that causes unusual flexibility and thin skin.

A prothrombin time test tells you how long it takes your blood to clot. Learn what it looks for, when you might need one, and what the results mean.

Having a nuclear kidney nuclear medicine scan? Find out how to prepare and what to expect.

An amylase test can tell your doctor about your pancreas -- and more. Find out why and how the test is done.

If you’re having certain symptoms like stomach pain or diarrhea, your doctor might order a gastrin test. Here’s what to expect and what the results may mean.

Sickle cell disease can lead to serious complications. Here are the options to treat and to cure it.

Sickle cell disease is the most common blood disorder passed down from parents to children. Learn how a gene mutation causes it.

Sickle cell crisis can be very painful and you never know when it might come on. Learn the symptoms, what to do when you have a crisis, and how you can help prevent it.

Sickle cell disease symptoms range from extreme pain to fatigue and fussiness in babies. Learn how to spot the symptoms of this blood disorder.

If you’ve experienced constipation, nausea, bloating, abdominal pain, diarrhea or heartburn, you may need a bowel transit time test to learn about the source of your discomfort. Here’s what you need to know about this test.

The sickle cell trait is passed down through families. Learn how you inherited this trait and how it differs from sickle cell disease.

When you have iron deficiency anemia, your body doesn't get the oxygen it needs. Learn what causes this type of anemia, and how to treat it.

Does your child have a bright red, bumpy rash? It could be scarlet fever, that's caused by the same bacteria that causes strep throat.

Does your child have a bright, red rash? It could be scarlet fever. Here's a look at the main symptoms of this infection.

Rubella is a contagious childhood infection caused by a virus. Learn why it can be serious during pregnancy, and how to avoid catching it.

Magnesium plays a key role in health, but many people don’t have enough in their bodies. Your doctor will use a magnesium test, usually a blood test, to find out your level.

Prealbumin is a protein produced by your liver. The prealbumin blood test analyzes the amount of this protein in your blood, which can help your doctor understand your diet.

Most bacteria that live in your body are harmless. Some are even helpful. Still, bacteria can infect almost any organ. Learn how antibiotics can help you get rid of them.

Your newborn will get hearing tests. Find out what happens, what the results mean, and what to expect.

WebMD explains sepsis, a severe blood infection that can lead to organ failure and death.

An immunoglobulin test checks how well your immune system works. Learn why you might need this test.

Hearing loss is common among adults and can be caught with a hearing test. Find out what happens during the test, how often they’re given and what follow-up may be needed.

Adults can have different degrees of hearing loss, from mild to profound. Learn which sounds people aren’t able to hear with different degrees of hearing loss.

An MRI can help your doctor diagnose you and monitor your treatment, but it isn't right for everyone. Learn what you should talk to your doctor about and when you should avoid this test.

Pseudomonas aeruginosa is a drug-resistant germ. Here's what to know about preventing and dealing with Pseudomonas aeruginosa.

Lactic acid is perfectly safe at low levels, but it can cause major problems when it builds up. If your doctor suspects that this is the case, you’ll probably have a lactic acid blood test.

An MRI is a common test that lets doctors see inside your body. Find out how they use it and how to prepare for an MRI.

If you have constant stomach problems, you may have diverticular disease. Find out what it is, what the symptoms are, and how it’s treated.

Chondrodysplasia is a collection of diseases that can affect a person’s stature, and, with some forms, many other aspects of their health.

How much do you know about mononucleosis? Get the facts on "mono" from the experts at WebMD.

An iron blood test can show whether you have too much or too little of this important mineral in your blood. Find out why your doctor might call for this test, and what the results mean.

Vitamin B12 deficiency anemia can make you feel tired, weak, and short of breath. Learn what triggers this type of anemia, and how to treat it.

Your doctor may suggest an ACTH test to find out if you have too much or too little cortisol. Learn what to expect and what you can learn from this blood test.

Too much or too little of growth hormone may cause metabolism or development issues. Here’s what you should know about GH testing.

A ferritin blood test shows how much iron is stored in your body. Find out why you might need this test and how it’s done.

It can be hard to tell if an injured toe is broken or just badly hurt. Learn the symptoms of a broken toe, when to call your doctor, and how to best care for it.

Malaria pills lower your chance of getting sick with the tropical disease. Although they aren’t 100% effective, they are an important way to reduce your chances of getting malaria while traveling.

Von Willebrand disease is a lifelong bleeding disorder. Learn about the different types of this condition, as well as its causes and treatments.

So, you think you have a urinary tract infection (UTI). Should you take a UTI home test, or wait to see your doctor? Find out whether these home tests are effective and what your next steps should be.

Malaria can be serious and sometimes life-threatening. Learn more about the disease and its new vaccine.