1)fresh urine → sampling → determination of Na, K and Cr. concentration using conventional method in the laboratory → results

2)fresh urine → sampling → absorption(with No.6 Toyo filter paper) → drying(naturally in room temperature) → wrapping(in alumium foil) → transportation(by mail to the laboratory) → storage(in a cold 5-10C place) → extraction(from filter paper with blank solution 25C, 60min.)(Na 100-107%　K 100-106% Cr. 98-102%) → determination of Na, K and Cr. concentratuion using routine method in the laboratory →results

3)correlation of results between Filter Paper Method anf convertional method

　 Number=48

　 NaCl/Cr.　r=0.999

　 K/Cr.　　 r=0998

　 Na/K　　 r=0.998

Reference

1) TAKEMORI, Koichi:Collection and transportation of urine samples by filter paper absorption method. Jpn. J. Hyg.,35, 721-727, 1989.