Objective: It is important to choose the correct screening titer in immunoflourescent assay for ANA. Recently, the use of 1:160 titer became widespread in the world, particularly after the suggestion of CDC (Centers for Disease Control and Prevention) and WHO (World Health Organization). In our country, 1:100 is the mostly used titer for screening as a cut off point. In this study, our aim was to investigate the convenience of suggested 1:160 screening titer for our country. Methods: In order to donate blood 200 out of 400 patients who are healthy blood donors confirmed consent form and applied to between Jan. and Feb. 2015. The rest of the patients has been diagnosed or followed autoimmune rheumatic diseases for the first time and approvaled the form. ANA test which is taken from the serum samples of the donors and patients worked by 1:100 and 1:160. It was figured out the sensitivity and specificity of the ANA as as result of ANA Hep-2 test taken from by donors and patients. Besides cut-off values of the test was determined with ROC curve analyze. Results: IIn healthy group the frequency of positivity is 8%, whereas in patients group it is 96%. In healthy group distribution of ANA titer positivity is: in 1:100 titer 44 %, in 1:160 37%, in 1:320 13% and in 1:640 6%. In healthy group in 1:160 distribution of ANA patern is: dense fine speck (dfs 70) 56%, speckled 25%, nucleolar 12,5%, centromere 6.5%. In patients' group distribution of ANA titer positivity is: in 1:100 0,5%, in 1:160 3%, in 1:320 26%, in 1:640 25%, in 1:280 34,5%, in 1:2560 8% and in 1:5120 3%. In patients group in 1:160 distribution of ANA patern is: speckled 55%, homogeneous 24%, nucleolar 11%, centromere 5%, nuclear dots 3% and nuclear membrane 2%. As a result of this study in healthy group, the most common patern is dense fine speck (dfs 70) and In patients' group is homogenous and speckled as expected. At 1:100 titer screening, sensitivity is 87,2 and specifity is 67,7 and At 1:160 titer screening, sensitivity is 74 and specifity is 85,8. According to ROC curve anal. 1:160 titer is detected. Conclusion: In this study, the screening titer of 1:160 for ANA test was confirmed by ROC Curve analyze. The screening titer of 1:160, as proposed by ICAP. It has been proposed to study a large group including more population.