[Report on the accuracy and the reliability of dip sticks]

Urinary examination with dip sticks is essential for clinical screening test and primary health care. Recently Japanese Society of Clinical Pathology has stressed the clinical use of dip sticks. Many dip sticks are available in Japan. However, few attempts have been done for external quality control of dip sticks. It is well known that there are considerable differences in the accuracy, sensitivity and stability of dip sticks. Makers are at variance in indicating concentration levels in accordance with the given color charts. Some urine chemistry analyzers for dip sticks have been developed. There was a few cases of simultaneous study on dip sticks from various makers. We, four technologists have attempted external quality control of eleven dip sticks for protein, glucose and occult blood with the same lot number (one was only for glucose) using the four different pooled urine samples and two artificial urine samples. Based on the results of this study, the following proposal to improve the accuracy and reliability of dip sticks was derived. 1) Users should have a plenty of knowledge on the difference of the quality of dip sticks of each makers. 2) Makers of dip sticks should clarify to users the method of examination, standard materials and errors. 3) Users should perform internal quality control using different pooled urine samples or different artificial urine samples on a daily basis before going with the routine work.