Choudhary S, Gibson P R, Deacon M C, Young G P
University of Melbourne Department of Medicine, Royal Melbourne Hospital, Victoria, Australia.
J Gastroenterol Hepatol. 1996 Apr;11(4):311-8. doi: 10.1111/j.1440-1746.1996.tb01377.x.
Presence of the serum protein, alpha 1-antitrypsin, in the faeces is a potentially useful marker for gastrointestinal disease and/or blood loss. In an effort to simplify faecal sampling procedures, we evaluated the performance of measuring alpha 1-antitrypsin in eluants of thin smears of faeces made on filter paper, relative to conventional measurement in aqueous extracts of stool. Faecal specimens and smears were collected from healthy subjects (n = 22) and from patients with gastrointestinal bleeding (n = 12) or inflammation (n = 22), colorectal neoplasia (n = 15), or miscellaneous diseases with a low risk of excessive faecal protein loss (n = 30). alpha 1-Antitrypsin was measured by ELISA and haem porphyrins (as a measure of blood loss) by HemoQuant. Results from smears were highly correlated (r = 0.81; P < 0.001) with faecal alpha 1-antitrypsin. The smear method detected an elevated faecal alpha 1-antitrypsin with 93% specificity and 75% sensitivity. Sensitivity was high ( > 88%) where levels were markedly elevated in inflammatory and bleeding groups and low ( < 62%) where abnormal levels were mildly elevated (neoplasia and miscellaneous groups). Elevated alpha 1-antitrypsin detection by either method positively predicted > 90% of patients with gastrointestinal inflammatory disease when levels were elevated 6-fold and 1.5-fold or more, respectively. In 15 patients with colorectal neoplasia, faecal alpha 1-antitrypsin was elevated in 10 patients, haem porphyrins in nine patients and either in 12; however, smear eluant levels were elevated in only six patients. Blood loss was probably a major contributor to elevated faecal alpha 1-antitrypsin in some patients but not in the inflammatory group as a whole. The sampling and aesthetic advantages of the smear eluant method are offset by reduced sensitivity, precluding its use as a screening test for colorectal neoplasia. However, its performance in predicting inflammatory disease is equivalent to that of conventional measurement and warrants a prospective evaluation as an early investigative test. Concurrent evaluation of blood loss may improve its interpretation.
粪便中存在血清蛋白α1-抗胰蛋白酶是胃肠道疾病和/或失血的一个潜在有用标志物。为了简化粪便采样程序，我们评估了在滤纸上制作的粪便薄涂片洗脱液中测量α1-抗胰蛋白酶的性能，与粪便水提取物中的传统测量方法相比。从健康受试者（n = 22）、胃肠道出血患者（n = 12）或炎症患者（n = 22）、结直肠肿瘤患者（n = 15）或粪便蛋白过度丢失风险较低的其他疾病患者（n = 30）中收集粪便标本和涂片。通过ELISA测量α1-抗胰蛋白酶，通过HemoQuant测量血红素卟啉（作为失血的指标）。涂片结果与粪便α1-抗胰蛋白酶高度相关（r = 0.81；P < 0.001）。涂片法检测粪便α1-抗胰蛋白酶升高的特异性为93%，敏感性为75%。在炎症和出血组中水平显著升高时敏感性较高（> 88%），而在异常水平轻度升高时（肿瘤和其他组）敏感性较低（< 62%）。当水平分别升高6倍和1.5倍或更多时，两种方法检测到的α1-抗胰蛋白酶升高对胃肠道炎症性疾病患者的阳性预测率均> 90%。在15例结直肠肿瘤患者中，10例患者粪便α1-抗胰蛋白酶升高，9例患者血红素卟啉升高，12例患者两者之一升高；然而，涂片洗脱液水平仅6例患者升高。失血可能是一些患者粪便α1-抗胰蛋白酶升高的主要原因，但并非整个炎症组。涂片洗脱液法的采样和美观优势被敏感性降低所抵消，使其无法用作结直肠肿瘤的筛查试验。然而，其在预测炎症性疾病方面的性能与传统测量方法相当，值得作为一项早期调查试验进行前瞻性评估。同时评估失血情况可能会改善其解读。
