Establishment of an Experimental Procedure for Preparing Trial Serum Samples for the Specific Serodiagnosis of Toxocara Canis for External Quality Assessment Schemes



Vu Quang Huy1, 2, 3, *, Tran Diep Tuan1, Tran Phu Manh Sieu1, 4, Le Van Chuong1, 2, Huynh Thi Diem Phuc3, Bui Quang Sang3, Nguyen Nhat Giang5
1 HCMC University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam
2 HCMC University Medical Center, Ho Chi Minh City, Vietnam
3 Quality Control Center for Medical Laboratory under supervision of the Ministry of Health –HCMC University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam
4 Nguyen Trai Hospital, Ho Chi Minh City, Vietnam
5 Da Nang University of Medical Technology and Pharmacy, Da Nang, Vietnam

Abstract

Background:

External quality assessment (EQA) provides evidence of reliable, accurate and precise results for customers using the diagnostic test for Toxocara canis.

Objective:

To establish a procedure for producing standard Toxocara canis serum samples for serodiagnostic testing in EQA.

Methods:

The collected serum samples thought to contain anti-Toxocara canis antibodies were screened by ELISA and confirmed by Western blotting. These samples were found to be negative for other helminth antibodies, anti-HIV-1 and -2 antibodies, anti-HCV antibodies, and antibodies to HBs antigen. The sera were divided, processed by both freeze-drying and freezing methods, and then stored. The stability and homogeneity of the samples were evaluated after 7 days, 1 month, 3 months and 6 months, respectively. An F-test and a T-test were applied to evaluate their homogeneity and stability.

Results:

Among the eleven samples confirmed positive by ELISA, ten of them were confirmed through Western blotting by positive reaction with 5 specific Toxocara canis bands. Two lots of trial standard sera containing specific anti-Toxocara canis antibodies were successfully produced. Lot DK had a concentration of 31.012 ± 1.14 NovaTec Units (NTU), and Lot DL had a concentration of 27.184 ± 0.994 NTU. After storage at -80°C, the samples prepared by the freeze-drying method were stable for at least 3 months, and the samples prepared by the freezing method were stable for 6 months (p>0.05). Samples produced by both methods were stable for 7 days at 30°C (p>0.05).

Conclusion:

Specific serodiagnosis samples of anti-Toxocara canis antibodies for EQA could be produced that possessed homogeneity and stability lasting for 3 months and 6 months by the freeze-drying and freezing methods, respectively. At 30°C, the samples produced by both methods were stable for 7 days, suitable for delivery to remote laboratories.

Keywords: ELISA, EQA, Toxocara canis, Western blot, trial serum samples, serodiagnosis.


Abstract Information


Identifiers and Pagination:

Year: 2019
Volume: 7
Publisher Item Identifier: EA-TOPARAJ-2019-2

Article History:

Received Date: 04/05/2019
Revision Received Date: 09/07/2019
Acceptance Date: 22/07/2019
Electronic publication date: 23/08/2019
Collection year: 2019

© 2019 Huy et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


* Address correspondence to this author at the Vu Quang Huy, HCMC University of Medicine and Pharmacy, 131 Nguyen Chi Thanh Street, District 5, Ho Chi Minh City, Vietnam; Tel: (+84) 913586389; Email: drvuquanghuy@gmail.com.