MCTD is not diagnosed unless the anti rnp antibody shows up. Maybe something to watch but if your symptoms continue you probably should get a 2nd opinion and talk about taking something to get your immune system under control. Whether or not you just have lupus or an overlap syndrome like MCTD treatment would probably be the same.
Labs alone do not mean you have something. Docs will look at clinical symptoms first and use labs or other tests to confirm a diagnosis and start treatment.
MCTD can present with symptoms of SLE lupus, scleroderma, polymyositis or sometimes RA or dermatomyositis. Every case is different and most likely you will not have all possible symptoms. I presented with lupus and then PM....
MCTD (SLE Lupus, polymyositis, scleroderma). Diagnosed 2005. Kidney, liver, GI tract, dysphagia, raynauds, barretts esophagus, quadriplegic in 2005. Recovered and now active in downhill skiing, golf, hiking. Meds: amlodipine, benezapril, omeprazole, potassium, folic acid, vitamins, maxide.
Remain Optimistic and you can overcome.