Rheumatic diseases are a large group of common diseases, multi-morbidity, and most of them require a series of laboratory tests to confirm the diagnosis. Since the diagnosis and treatment of rheumatic diseases started late in China, many large hospitals have not yet established rheumatology specialists. In recent years, a variety of laboratory indicators for early diagnosis of rheumatic diseases and to help determine the prognosis of the disease have been discovered. Not only do most patients not understand rheumatic disease laboratory tests, but even doctors of other specialties cannot understand these tests correctly. The most common of the rheumatology laboratory tests is the detection of various autoantibodies. The so-called autoantibodies are the overreaction of our own body’s defense tissues, which produce resistance to the normal tissues in the body, or autoantibodies, which are used to destroy these normal tissues. Autoantibody testing is essential for the diagnosis of rheumatic diseases, especially for diffuse connective tissue diseases. Nowadays, the main autoantibodies applied in rheumatology clinic are: rheumatoid factor, anti-keratin antibody profile, anti-nuclear antibody profile, anti-neutrophil cytoplasmic antibody, antiphospholipid antibody, etc. Rheumatoid factor (RF) Rheumatoid factor was originally found in the serum of patients with rheumatoid arthritis (RA), so it is thought that it can be used to diagnose rheumatoid arthritis. Currently RF has some value as a screening test for RA, and at least 75% of RA patients are positive for RF. The American College of Rheumatology (ACR) has proposed seven criteria for the diagnosis of RA, of which a positive RF is one, and those who meet four of them can be diagnosed with RA. The presence of RF in RA patients suggests a poor prognosis, and also suggests that the patient may have not only joint symptoms, but also extra-articular manifestations, that is, manifestations of multisystem involvement. And as the duration of joint symptoms in RA patients increases, the rate of RF also increases, such as: 33% at 3 months, 75% at 1 year, 90% at 18 months. Therefore, when the first test result is negative but still highly suspicious clinically, repeated testing for RF has some significance. RA cannot be diagnosed solely on the basis of a positive RF, i.e., not a positive RF with arthralgias must be RA, while a negative RF must not be RA, because RF can also be present in the following diseases: dry syndrome, mixed connective tissue disease, systemic sclerosis, acute viral infections, parasitic infections, chronic inflammatory diseases, tumors, other hyperglobulinemic status, chronic liver disease, about 5% of the elderly can also appear positive for RF. The anti-keratin antibody spectrum includes anti-keratin antibodies (AKA), anti-perinuclear factor antibodies (APF) and anti-CCP antibodies, which are autoantibodies used in the early diagnosis of RA and can assist in RF, improve the early diagnosis of RA, early and correct treatment and improve the prognosis. Anti-nuclear antibody spectrum Anti-nuclear antibody (ANA) refers to the nucleus and the components of the nucleus, and ANA refers to antibodies against the components of the nucleus. Patients with positive ANAs should consider the possibility of connective tissue disease, but should be verified as positive by multiple laboratory tests. In addition, low titers of ANAs may be present in the sera of normal elderly or other non-connective tissue disease patients; therefore, ANAs should be measured and reported in titers. ANAs are classified into four categories: anti-DNA, anti-histone, anti-nonhistone, and anti-nucleolus antibodies, based on the physicochemical properties and distribution of various components in the nucleus and their clinical significance. Among them, anti-nonhistone antibodies are often seen and used as anti-ENA antibodies. For patients with positive ANAs, in addition to testing titers, it is important to distinguish which class they are. Different categories of ANAs have different clinical significance and have different diagnostic value. Anti-DNA antibodies, especially anti-dsDNA antibodies, are specific diagnostic antibodies for SLE and have a strong diagnostic value for lupus nephritis. Patients with anti-histone antibodies positive for lupus erythematosus are most often considered to have the possibility of drug-induced lupus. Positive anti-nucleolin antibodies are mostly seen in patients with systemic sclerosis. Among the anti-ENA antibody profile, anti-Sm antibody was first found in the serum of a patient with SLE named Smith, and later found to be useful for the diagnosis of SLE with high specificity; anti-SSA and SSB antibodies are two autoantibodies used for the diagnosis of patients with desiccation syndrome; anti-RNP antibody can be used for the diagnosis of mixed connective tissue disease; positive anti-Jo-1 antibody can help anti-Jo-1 antibody can help diagnose polymyositis/dermatomyositis; anti-Scl-70 antibody can be used for the diagnosis of systemic sclerosis. Anti-neutrophil cytoplasmic antibodies Anti-neutrophil cytoplasmic antibodies (ANCA) are useful in the diagnosis and determination of activity of vasculitic disease, especially Wegener’s granulomatosis. Antiphospholipid antibodies are associated with thrombocytopenia, arteriovenous thrombosis, and habitual spontaneous abortion. The above-mentioned antibodies are extremely valuable for the diagnosis of rheumatic diseases, but there is a range of sensitivity and specificity, and the technique of detection can also cause false-positive and false-negative results, so the diagnosis of rheumatic diseases still has to be made through the combination of clinical and laboratory autoantibodies.