女性的污染尿液樣本對急診尿路感染診斷的影響

Contaminated Urine Specimens in Emergency Room Interfere with the Interpretation of Urinary Tract Infection

尿液是臨床上最常見的檢驗與細菌培養的檢體。女性較特殊生理結構，常易受會陰部上皮細胞的污染，也同時對尿路感染判讀產生影響。我們嘗試由常見的尿液中出現鱗狀上皮細胞（檢體受到污染）的狀況下，試著找出好的判讀標準。本研究由急診室連續選取做尿液檢查的女性病患，檢體中的鱗狀上皮細胞超過可接受的範圍，即一般所認為女性病患在留取檢查，未注意留到清潔與中段尿時受到污染的檢體。以每一位病患的臨床上是否有感染與否做一比對。同時並比對尿白血球酯酶以及亞硝酸鹽快速檢查，與感染與否的相關性。總共有175位女性病患收錄在本研究中，平均年齡為44.3±17.6歲（20到90歲）。有72位判定為尿路感染(41.1%)，有103位(58.9%)判定非尿路感染。白血球酯酶陰性有20位，白血球酯酶微陽性(trace)有41位，白血球酯酶陽性一價有39位，白血球酯酶二價75位，以Mann-Whitney U檢定，不具統計顯著差異(P=0.331)。以亞硝酸鹽(nitrite)的差異來看，亞硝酸鹽陰性有162位，亞硝酸鹽陽性13位，判斷感染統計上，以Mann-Whitney U檢定無顯著差異(p=1.00)。將白血球酯酶以及亞硝酸鹽以聯集方式合併，以Mann-Whitney U檢定無顯著差異(p=0.710)。女性在進行尿液檢查時，應注意清潔以及留取中段尿，否則用各種方式來校正的效果，都達不到預期的檢查效果。

Urine specimens are one of the most common specimens that undergo analysis and microbial culture. However, in women, this analysis is susceptible to contamination by epithelium around the urethra meatus. This can interfere with interpretation. In this study, we attempt to identify correction criteria from urine specimens that will detect epithelial cells in contaminated specimens. We collected urine specimens with epithelial cells contamination, consecutively from the women who visited the emergency room. These were split into two groups based on clinical infection during diagnosis and compared. The aim was to try and identify whether a leukocyte esterase and/or a nitrite test was able to help clarify the diagnosis in a contaminated or allow modification of the test results. The study included a total of 175 women with an average age of 44.3±17.6 years (range 20 to 90). Of these, 72 women were diagnosed with urinary tract infection (41.1%) and 103 (58.9%) women were diagnosed as being without infection. In total, there were 20 persons that showed up as negative for leukocyte esterase, 41 showed up with a trace of the enzyme, 39 showed up with one positive for the enzyme and 75 showed up with two positives for the enzyme. No significance was found by the Mann-Whitney U test (p=0.33). A similar approach was carried out for nitrite and there were negative nitrite results for 162 women, and positive results for 13 individuals. This result also shows no significance by the Mann-Whitney U test (p=1.00). Finally, even when the results were combined, no significance was found.We failed to find any correction criteria to improve urine specimen analysis. It is essential that women collect their urine sample correctly without contamination.