Does this test have other names?
Lithium levels, serum lithium levels, lithium blood test
What is this test?
This test measures and monitors the amount of lithium in your blood.
Lithium is a medicine used to treat psychiatric illnesses such as bipolar disorders,
acute mania, and other mood disorders. This test is used to find out the right dose
for you if you're just starting lithium treatment. The test is also used to make sure
you continue to get the right amount for as long as you take this medicine.
If you take too much lithium, it can cause more side effects. If you take too little,
the drug might not help your condition.
Why do I need this test?
You may have this test once or twice a week when you first start taking lithium to
help your healthcare provider figure out the best dose for you.
You may also have this test after you've been taking lithium for a while to see whether
your dose needs to be changed. You may have this test again 5 to 7 days after your
dosage is changed.
You may also have this test if you have symptoms such as tremor, nausea, vomiting,
or diarrhea. This will let your healthcare provider know if your symptoms are because
your lithium level is too high or if you have other conditions that need to be treated.
What other tests might I have along with this test?
Your healthcare provider may also order tests that check how well your kidneys and
other organs are working. This is because lithium is excreted through your kidneys.
It is not metabolized. These tests may include:
Your provider may also order a pregnancy test, because you shouldn't take lithium
during the first 3 months of pregnancy.
Your provider may also order other tests while you're taking lithium, to watch how
your kidneys and thyroid are working:
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses
to do the test. Even if your test results are different from the normal value, you
may not have a problem. To learn what the results mean for you, talk with your healthcare
Results are given in milliequivalents per liter (mEq/L). For lithium to be effective,
your level should be between 0.6 and 1.2 mEq/L, but not more than 1.2 mEq/L.
Lithium has a very narrow range where it is effective and nontoxic. At a level of
1.2 mEq/L, lithium can start to cause problems.
If your levels are too high, you could get lithium poisoning and need treatment right
away. Too much lithium can be fatal. If your levels are too low, the medicine may
not help your condition.
Levels that are higher or lower may also mean you have cardiovascular or kidney disease.
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection,
bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight
stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
Timing is important. Having the test 12 hours after your last dose of lithium gives
the best results.
Certain medicines can affect your results. These include:
Dilantin, for epilepsy
Water pills (diuretics)
Nonsteroidal anti-inflammatory medicines, except aspirin
Cardiovascular medicines. These include angiotensin converting enzyme (ACE) inhibitors
and calcium channel blockers
Being dehydrated or a diet too high or low in salt can also affect your results.
How do I get ready for this test?
You don't need to prepare for this test, but note the time you took your last dose
of lithium. In addition, be sure your healthcare provider knows about all medicines,
herbs, vitamins, and supplements you are taking. This includes medicines that don't
need a prescription and any illicit drugs you may use.