{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:38:59Z","timestamp":1787027939899,"version":"build-2736575974"},"reference-count":14,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2014,1,9]],"date-time":"2014-01-09T00:00:00Z","timestamp":1389225600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Neutral a-glucosidase (NAG) activity in human seminal plasma is an important indicator for epididymis functionality. In the present study, the classic World Health Organization (WHO) method has been adapted to enhance assay robustness. Changes include modified enzyme reaction buffer composition and usage of an alternative enzyme inhibitor for background correction (glucose instead of castanospermine). Both methods have been tested in parallel on 144 semen samples, obtained from 94 patients\/donors and 50 vasectomized men (negative control), respectively. Passing-Bablok regression analysis demonstrated equal assay performance. In terms of assay validation, analytical specificity, detection limit, measuring range, precision, and cut-off values have been calculated. These data confirm that the adapted method is a reliable, improved tool for NAG analysis in human semen.<\/jats:p>","DOI":"10.3390\/diagnostics4010001","type":"journal-article","created":{"date-parts":[[2014,1,9]],"date-time":"2014-01-09T14:10:57Z","timestamp":1389276657000},"page":"1-11","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["An Improved Neutral a-Glucosidase Assay for Assessment of Epididymal Function\u2014Validation and Comparison to the  WHO Method"],"prefix":"10.3390","volume":"4","author":[{"given":"Frank","family":"Eertmans","sequence":"first","affiliation":[{"name":"Department of Research and Development, FertiPro NV, Industriepark Noord 32, 8730 Beernem, WVL, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Veerle","family":"Bogaert","sequence":"additional","affiliation":[{"name":"Department of Research and Development, FertiPro NV, Industriepark Noord 32, 8730 Beernem, WVL, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tanita","family":"Van Poecke","sequence":"additional","affiliation":[{"name":"Laboratory of Andrology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, OVL, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barbara","family":"Puype","sequence":"additional","affiliation":[{"name":"Department of Research and Development, FertiPro NV, Industriepark Noord 32, 8730 Beernem, WVL, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2014,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1002\/j.1939-4640.1984.tb00789.x","article-title":"Similar biochemical properties of human seminal plasma and epididymal alpha-1, 4-glucosidase","volume":"5","author":"Paquin","year":"1984","journal-title":"J. Androl."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1002\/j.1939-4640.1988.tb01016.x","article-title":"Epididymal markers in human infertility","volume":"9","author":"Cooper","year":"1984","journal-title":"J. Androl."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1111\/j.1365-2605.1990.tb01035.x","article-title":"Improvement in the assessment of human epididymal function by the use of inhibitors in the assay of alpha-glucosidase in seminal plasma","volume":"13","author":"Cooper","year":"1990","journal-title":"Int. J. Androl."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"156","DOI":"10.1002\/j.1939-4640.1986.tb00901.x","article-title":"Alpha-glucosidase as a specific epididymal enzyme marker. Its validity for the etiologic diagnosis of azoospermia","volume":"7","author":"Guerin","year":"1986","journal-title":"J. Androl."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"324","DOI":"10.1016\/S0015-0282(16)50013-2","article-title":"Simultaneous measurement of seminal L-carnitine, alpha,1\u20134-glucosidase, and glycerylphosphorylcholine in azoospermic and oligozoospermic patients","volume":"47","author":"Casano","year":"1987","journal-title":"Fertil. Steril."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1070","DOI":"10.1093\/oxfordjournals.humrep.a138194","article-title":"Disturbances of sperm flagella due to failure of epididymal maturation and their possible relationship to phospholipids","volume":"7","author":"Haidl","year":"1993","journal-title":"Hum. Reprod."},{"key":"ref_7","unstructured":"Cooper, T.G. (2010). WHO Laboratory Manual for the Examination and Processing of Human Semen, WHO Press. [5th ed.]."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"8264","DOI":"10.1021\/bi201284u","article-title":"The original Michaelis constant: Translation of the 1913 Michaelis\u2013Menten paper","volume":"50","author":"Johnson","year":"2011","journal-title":"Biochemistry"},{"key":"ref_9","unstructured":"(2008). Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory: Approved Guideline, Clinical and Laboratory Standards Institute (CLSI). [3th ed.]. Document C28-A3."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"459","DOI":"10.2164\/jandrol.04104","article-title":"A review of the physical and chemical properties of human semen and the formulation of a semen simulant","volume":"26","author":"Owen","year":"2005","journal-title":"J. Androl."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/S1570-9639(02)00474-0","article-title":"Multiple sugar binding sites in alpha-glucosidase","volume":"1645","author":"Yao","year":"2003","journal-title":"Biochim. Biophys. Acta"},{"key":"ref_12","first-page":"709","article-title":"A new biometrical procedure for testing the equality of measurements from two different analytical methods. Application of linear regression procedures for method comparison studies in Clinical Chemistry, Part I","volume":"21","author":"Passing","year":"1983","journal-title":"J. Clin. Chem. Clin. Biochem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1093\/clinchem\/24.2.208","article-title":"P-Nitrophenol-alpha-D-glucopyranoside as substrate for measurement of maltase activity in human semen","volume":"24","author":"Chapdelaine","year":"1978","journal-title":"Clin. Chem."},{"key":"ref_14","first-page":"S23","article-title":"Evaluating assay precision","volume":"29","author":"Chesher","year":"2008","journal-title":"Clin. Biochem. Rev."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/4\/1\/1\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:07:14Z","timestamp":1760216834000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/4\/1\/1"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2014,1,9]]},"references-count":14,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2014,3]]}},"alternative-id":["diagnostics4010001"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics4010001","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2014,1,9]]}}}