To help in the diagnosis and monitoring of drug-induced lupus
Histone Antibody
Histone Antibody
Also Known As
Histone Autoantibodies
Formal Name
Antihistone Antibody
This article was last reviewed
on
This article waslast modified
on September 17, 2018.
At a Glance
Why Get Tested?
When To Get Tested?
When you have symptoms associated with lupus that may be due to a drug that you are taking
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None
Accordion Title
Common Questions
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How is it used?
Histone antibody testing is primarily used to support a diagnosis of drug-induced lupus, particularly in a person who is taking one of the medications mentioned above in the "What is being tested?" section.
Testing is used to distinguish drug-induced lupus from other forms of lupus such as systemic lupus erythematosus (SLE), from another autoimmune disorder, or from another cause of a person's symptoms. While it is not diagnostic of drug-induced lupus, its presence is consistent with this diagnosis.
The test is typically ordered with or following a positive ANA test and may be ordered along with a test for anti-double-stranded DNA (anti-dsDNA) to help establish a diagnosis.
If a person is diagnosed with drug-induced lupus, the identified drug may be discontinued upon the recommendation of the healthcare practitioner. One or more histone antibody tests may be used as follow up to monitor antibody levels (titers), if present.
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When is it ordered?
A histone antibody test is ordered when a person has been taking a drug for several weeks to a couple of years and develops signs and symptoms that could be due to drug-induced lupus. This is especially true when the person affected did not have a prior personal or family history of an autoimmune disorder. Symptoms may include:
- Arthritis-like pain in one or more joints (but no or little joint inflammation)
- Fatigue
- Fever
- Muscle pain (myalgia)
- Red rash that frequently resembles a butterfly across the nose and cheek areas (malar rash)
- Sensitivity to sunlight
- Weight loss
Symptoms and complications involving the central nervous system (CNS) and kidneys occur with SLE but are much rarer with drug-induced lupus.
The histone antibody test may be repeated at intervals after the drug has been discontinued to monitor for decreases in histone antibody levels.
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What does the test result mean?
Results of histone antibody testing consider several factors. A positive result means that a person likely has drug-induced lupus if the person also has:
- Symptoms associated with lupus
- Been taking a drug, especially one associated with the condition, for several weeks to a couple of years
- No identified autoimmune disorder prior to taking the drug
- Positive ANA test
- Low or negative anti-dsDNA and other autoantibodies
- Signs and symptoms that resolve when the drug is discontinued
- Histone antibody levels that begin to decrease when the drug is discontinued
A positive histone antibody result by itself does not establish a diagnosis. About 50% of those with SLE will have histone antibodies, though generally not induced by a specific drug. In these cases, the anti-dsDNA test will be positive and significantly elevated.
A negative result means that the individual's signs and symptoms may be due to a condition other than drug-induced lupus, such as a drug allergy. However, a negative result does not rule out drug-induced lupus. A small portion of individuals may have drug-induced lupus even if they do not have histone antibodies.
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Is there anything else I should know?
An individual with SLE may have a flare-up that is caused or exacerbated by drug therapy without having drug-induced lupus.
SLE tends to affect more women than men and tends to occur in people in their 20s to 40s. Drug-induced lupus affects both sexes equally and can affect anyone but occurs most frequently in those who are older.
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What can I do to change my histone antibody level?
Talk to your healthcare practitioner about discontinuing the potentially offending drug. When this is done, the histone antibody level should drop over time. Histone antibody levels do not respond to lifestyle changes.
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If the level of my histone antibodies decreases, can I take my drug again?
No. The antibodies may drop to very low or undetectable levels, but a small amount will still exist. If you resume taking your drug, your symptoms and increased antibody levels may reemerge.
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Should I tell all my healthcare providers about being diagnosed with drug-induced lupus?
Yes, this is an important part of your medical history and needs to be shared as it will need to be taken into account by your healthcare practitioners whenever you are given medications.
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How long will it take for my results?
It may take several days before your results are available. This is not a routine test and your sample will frequently need to be sent to a regional reference laboratory for testing.