External validation of the STONE score and derivation of the modified STONE score.
OBJECTIVE
The STONE score is a clinical prediction rule for the presence of uncomplicated ureter stones with a low probability of acutely important alternative findings. This study performed an external validation of the STONE score, focusing on the Korean population, and a derivation of the modified STONE score for better specificity and sensitivity.


METHODS
We retrospectively reviewed medical records of patients complaining of flank pain at a single emergency department from January 2013 to December 2014. Patients were categorized into 3 groups according to their STONE score. The prevalence of ureter stones and other alternative findings were calculated in each group. We derived a modified STONE score based on a multivariable analysis and performed an interval validation.


RESULTS
From the 700 patients included in the analysis, 555 patients (79%) had a ureter stone. The area under the receiver operating characteristic curve of the STONE score was 0.92. The sensitivity of the high stone score was 0.56. In the modified STONE score, nausea, vomiting, and racial predictors were substituted by C-reactive protein and previous stone history. The area under the receiver operating characteristic curve and sensitivity of the modified STONE score in the internal validation group significantly increased to 0.94 and 0.80, respectively.


CONCLUSIONS
The STONE score can be used to predict a ureter stone with a low probability of other alternative findings. The modified STONE score might increase the diagnostic performance in suspicious urinary stone cases.


CONCLUSIONS
We performed external validation of the STONE score and derivation of the modified STONE score. This scoring system could help the clinicians with radiation reducing decision making.
Department of Emergency Medicine, Seoul National University, Bundang Hospital, Sungnam-si, Gyeonggi-do 463-707, Republic of Korea. Electronic address: vogam0619@gmail.com.
Byunghyun
B
Kim
Department of Emergency Medicine, Seoul National University, Bundang Hospital, Sungnam-si, Gyeonggi-do 463-707, Republic of Korea. Electronic address: dremkks@snubh.org.
Kyuseok
K
Kim
Department of Emergency Medicine, Seoul National University, Bundang Hospital, Sungnam-si, Gyeonggi-do 463-707, Republic of Korea.
Joonghee
J
Kim
Department of Emergency Medicine, Seoul National University, Bundang Hospital, Sungnam-si, Gyeonggi-do 463-707, Republic of Korea.
You Hwan
YH
Jo
Department of Emergency Medicine, Seoul National University, Bundang Hospital, Sungnam-si, Gyeonggi-do 463-707, Republic of Korea.
Jae Hyuk
JH
Lee
Department of Emergency Medicine, Seoul National University, Bundang Hospital, Sungnam-si, Gyeonggi-do 463-707, Republic of Korea.
Ji Eun
JE
Hwang
Department of Emergency Medicine, Seoul National University, Bundang Hospital, Sungnam-si, Gyeonggi-do 463-707, Republic of Korea.
Jongdae
J
Park
D003657:Decision Making; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital; D005260:Female; D021501:Flank Pain / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014514:Ureteral Calculi / Q000150:complications / Q000175:diagnosis*