title: Use of blood collected onto and dried on filter paper for diagnosing pregnancy in cattle.
abstract: The measurement of serum or plasma pregnancy-associated glycoproteins (PAGs) is increasingly used to diagnose pregnancy in cattle. This study evaluated whether a dried blood spot (DBS) collected on filter paper could be used as an alternative to serum or plasma for such tests. A total of 37 serum, 68 plasma and 68 DBS samples were collected from cows of known pregnancy status and tested using a commercial ELISA. None of the plasma or serum samples resulted in false positives or false negatives. No false positives (sample-negative (S-N) values >0.3 in non-pregnant cows) were observed with DBS samples, but false negatives were observed (S-N values <0.3 in pregnant cattle). The data suggested that PAGs in DBS samples were diluted during processing as samples from pregnant cattle had lower S-N values (0.111-0.494) than the corresponding serum (1.123-2.665) and/or plasma (0.764-2.042) samples. ROC analysis showed that lowering the cut-off S-N value from 0.3 to 0.1 for DBS samples prevented false negatives without increasing false positives. Modifications to the test protocol significantly increased mean S-N values of DBS samples from pregnant cows while those from non-pregnant cows were not affected. In conclusion, lowering the cut-off and modifying the protocol allowed DBS samples to be used for blood-based pregnancy testing.
authors.affiliation: Department of Veterinary Diagnosis and Production Animal Medicine, Iowa State University, Ames, IA, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Sun
authors.forename: Yong-Il
authors.initials: YI
authors.lastname: Cho
authors.forename: Patrick
authors.initials: P
authors.lastname: Comyn
authors.forename: Kyoung-Jin
authors.initials: KJ
authors.lastname: Yoon
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D059788:Dried Blood Spot Testing / Q000379:methods* / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000662:veterinary; D005260:Female; D006023:Glycoproteins / Q000097:blood; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood
chemical_list: D006023:Glycoproteins; D011257:Pregnancy Proteins
keywords: Dried blood spot; ELISA; Filter paper sampling; PAG; Pregnancy testing