The diagnosis of FMF is established on clinical findings and supported by genetic testing. There are several sets of criteria established for the diagnosis of FMF, with the Tel-Hashomer criteria being the most common used . Although the Tel-Hashomer criteria were determined for adults, they are also used successfully in the diagnosis of pediatric patients. However, difficulties in expressing the severity and location of pain and determining the level of fever (axillary, rectal, etc.) complicate the use of Tel-Hashomer criteria in children. This reveals the necessity to identify more simple and practical diagnostic methods specific to children. In recent studies, the value and benefit of the Tel-Hashomer criteria in children have been investigated, and some new pediatric diagnostic sets of criteria have been described [3, 8, 10–12].
The pediatric criteria for the FMF diagnosis were established by Yalcınkaya et al.  in a 2009 study including Turkish pediatric patients. In that study, five diagnostic criteria were defined as recurrent fever, abdominal pain, arthritis, chest pain, and a family history of FMF. Their control group consisted of consecutive patients without FMF who had clinical features mimicking that of FMF, similar to our study. They compared their results to those of the Tel-Hashomer criteria and determined the sensitivity and specificity of diagnosis as 88.7% and 92.6% in patients meeting at least two of their five criteria (Table V). However, they stated that the results of this study should also be valid in different ethnic groups and populations. Our study revealed similar sensitivity (88.6%) and lower specifity (84.6%) compared to Yalcınkaya et al. .
There were three previous attempts to validate the pediatric criteria. Kondi et al.  evaluated 70% Sephardic Jews in an FMF group of patients in 2010 but they determined that the pediatric criteria did not make any further influence to the FMF diagnosis with compared to the Tel-Hashomer criteria and suggested the use of at least three of the Turkish pediatric criteria increased sensitivity to 77% and specifity to 95% (Table V). Demirkaya et al.  analyzed the largest number of pediatric patients with periodic fevers and with a various geographical and ethnic distribution in 2015. They showed that the pediatric criteria can be evaluated for the diagnosis of FMF, but it had higher sensitivity (87.4%) and lower specificity (40.7%), whereas the Tel-Hashomer criteria had lower sensitivity (45%) and higher specificity (97.2%). But Sag et al.  also evaluated pediatric criteria had higher sensitivity (93.4%) and lower specificity (84.1%), whereas the Tel-Hashomer criteria had lower sensitivity (88.7%) but higher specificity (92.6%) (Table V). We found using at least two of the pediatric criteria had 88.6% sensitivity and 84.6% specificity, which is consistent with the results presented by Yalcınkaya et al.  In contrast, we determined the specificity of the Tel-Hashomer criteria to be higher at 95.7%. The main reason for this difference may be that as the reference diagnostic criteria, we used the Tel-Hashomer criteria whereas Yalcınkaya et al.  used the Livneh criteria that are more detailed and comprehensive . However, the Livneh criteria can be more difficult to evaluate, especially in children. Therefore, using Yalcınkaya et al.’s criteria instead of the Livneh criteria may be simpler and more useful. We evaluated that the presence of at least two of the pediatric criteria were related to higher sensitivity (88.6%) than the Tel-Hashomer criteria (69.9%), confirming the findings of Yalcınkaya et al.  (86.5%), Demirkaya et al.  (87.4%)., and Sag et al.  (93.4%). but lower compared to Kondi et al. (100%). Contrary to the study of Kondi et al. , our study group consisted of Turkish patients with a homogeneous ethnic and geographical origin. The 2005 Turkish FMF study group revealed that 7.5% of FMF patients presented without fever, and this rate was higher than reported for the Jews, Arabs and Armenians . Kondi et al. , Demirkaya et al.  and Sag et al.  formed their control groups with patients with periodic fever syndromes or autoinflammatory disease. In contrast, similar to the study of Yalcınkaya et al , our control group was not limited to patients with periodic fever syndromes and autoinflammatory disease, and it represented a wide and heterogeneous population with a wide range of symptoms mimicking FMF, such as recurrent abdominal pain, fever, joint pain, and chest pain. The rates of a family history of FMF (20.5%) and consanguinity (20.5%) were high in our control group. Although the frequency of FMF in Turkish population is high, the sensitivity of pediatric criteria has been reported to be higher in other countries where FMF is rarely seen .
Similar to Kondi et al. , our results showed that the patients with mutations in two alleles and those with one allele had similar clinical characteristics, and genetic status had no effect on clinical findings. We also evaluated the new Eurofever/PRINTO classification criteria in our FMF group and found them to be sensitive and specific for the classification of FMF (Table III, IV). However, research suggests that these classification criteria simplify the identification of FMF in clinical, epidemiological and translational studies but cannot be used for routine diagnostic purposes in individual patients [9, 14]. Tanatar et al. investigated the Tel-Hashomer, Livneh, pediatric criteria and Eurofever/PRINTO criteria and found lower performance in both of four criteria in diagnosing and classifying heterozygous FMF patients . Sag et al.  also compared the Tel-Hashomer, pediatric and Eurofever/PRINTO criteria and found that the Eurofever/PRINTO criteria reached the highest sensitivity in biallelic mutation patients.
Our results confirm that the Eurofever/PRINTO classification criteria can be successfully used in the diagnosis of FMF due to their high sensitivity and specificity, as also suggested by the authors that developed this tool. In our evaluation of the pediatric criteria, we determined that the presence of at least two of these criteria was adequate for a diagnosis of FMF in children. Thus, our study supports both the use of pediatric criteria and Eurofever/PRINTO classification criteria in clinical practice.