[br>Thank you for asking this question. It is a very common scenario, and a lot of my patients are caught in the same situation that you are. The ophthalmologist's concerns stem from recent guidelines issued by the American Association of ophthalmology, which states that after 5 to 7 years of use, most people are at a higher risk for plaquenil induced retinal toxicity. However, the discontinuation of this drug is an individual decision that should be made between the patient, and all of her treating doctors. In this context, though the guidelines are very strict and are stricter than they have been in the past, they rely on newer diagnostic tests which are over sensitive in my experience. In some cases plaquenil induced retinal toxicity may not be reversible, and your optho is justified in expressing his concerns. However, plaquenil toxicity is extremely rare, and most ophthalmologists do not end up seeing a single case throughout their careers. If this is the most effective drug for your condition, you should definitely talk to your rheumatologist and ophthalmologist, and state your preferences. They should probably monitor you very carefully using the latest technologies to diagnose early retinal toxicity. However, bear in mind that they may pick up early changes that might not be meaningful in that they may never cause toxicity. The usual dose is 5 mg/kg of body weight with an increase to 7mg/mg for about 3 months to combat flare ups in your condition.
Anti-smith antibody is a specific auto-antibody for lupus and when present in high titres, could be associated with lupus kidney disease. In your case the titre is low, and I am not sure of the rest of your medical history. Just having this test does not make it certain that you have lupus and it needs to be looked at in the context of your other symptoms and blood tests. Please look at our previous posts on the topic of how to diagnose lupus.
Please let me know if you have any follow up questions.
I appreciate your asking this question, as it raises a relevant issue regarding diagnostic tests. As everyone who reads this board knows, diagnosing lupus is not an easy task as everyone presents with different manifestations and laboratory tests. So your story is not uncommon. Happily, we have made some progress in this direction and there are several "biomarkers" that are being studied to diagnose and monitor treatment of lupus. Biomarkers are lab tests or imaging tests that can show evidence of a disease process or disease activity.
1. You are right that we do not make the diagnosis of lupus based only on blood work. Typically, you need 4 criteria to make the diagnosis of lupus. The new SLICC clinical criteria for lupus from 2010 are highly specific. (good at predicting which people do not have the disease and those that have it) These criteria require that you have a total of 4 criteria to receive the diagnosis of lupus. Of these 4 criteria, at least one must be a clinical criteria (rash, arthritis etc) and at least one must be a lab criteria. (ANA, DNA etc) If you fulfill these criteria, assuming that other conditions presenting similary have been ruled out, (for example rheumatoid arthritis has been ruled out by negative tests and the clinical features and x ray/MRI features, or hepatitis infection has been ruled out) the likelihood that you have lupus is close to 90%.
2. The Avise SLE panel is a panel of 5 tests that are performed to diagnose lupus. The results of the 5 tests are analysed to create a composite score. If your score is above a certain threshold the Avise SLE test is considered to be positive. This "test" was literally put to the test in a large multi-center study of 593 patients. In this study, it was found that the sensitivity (the percentage of sick people who are correctly identified as having the condition) was 80% and the specificity (he percentage of healthy people who are correctly identified as not having the condition, sometimes called the true negative rate) was 87%. Thus, the Avise SLE test is a good test for diagnosing lupus and if positive the likelihood that you have lupus is quite high.
Hope this helps. Wishing you the best in your journey. View Thread
Anti-histoneantibodies can be seen in lupus. About 50% of lupus patients have antihistone antibodies. However, over 90% of patients with drug-induced lupus have antihistone antibodies. Having antihistone antibodies does not mean that you'll have drug-induced lupus, and they can certainly be seen in systemic lupus.[br>[br>In terms of the ANA being negative, while double strand DNA antibodies are positive, this is unlikely. It means, that the methodology being used by the laboratory to test the ANA, is faulty. In general, the best method of testing for an ANA is by immunofluorescence. However, I think that the ANA test being negative in your case, was a false negative. The double-stranded DNA antibodies and antihistamine antibodies are likely real.View Thread