Effect of Long-Term Freezing on Indirect Fluorescent Antibody Titers for the Diagnosis of Equine Protozoal Myeloencephalitis

IF 2.2 2区农林科学 Q1 VETERINARY SCIENCES

Journal of Veterinary Internal Medicine Pub Date : 2025-08-27 DOI:10.1111/jvim.70225

Claudia Valderrama-Martinez, Andrea Packham, Woutrina Smith, Jorge Eduardo Mendoza-Flores, Shichen Zheng, Munashe Chigerwe, Magdalena Plancarte, Monica Aleman

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引用次数: 0

Abstract

Background

Long-term freezing storage can alter the stability of proteins, thereby compromising accurate determination of indirect fluorescent antibody test (IFAT) titers that support the diagnosis of equine protozoal myeloencephalitis.

Objective

Assess the effect of long-term storage at −80°C on IFAT against S. neurona and N. hughesi in equine serum and cerebrospinal fluid (CSF).

Samples

Paired serum and CSF (n = 46), and serum only (n = 25) samples.

Methods

Prospective study of samples stored 6–12, 13–18, and 19–24 months. Comparing antibody titers across time points, McNemar and Wilcoxon rank tests were used for statistical analysis.

Results

After long-term freezing storage for 19–24 months, N. hughesi IFAT results for CSF were significantly different compared with their fresh-testing time point (p = 0.04), but a similar difference was not observed for serum samples. No statistical differences were observed for serum or CSF samples tested for S. neurona after 6–12, 13–18, or 19–24 months compared with their original fresh testing results. However, the serum to CSF ratio cutoff of ≤ 64 in support of disease changed in 41% (19 of 46) of paired samples.

Conclusions and Clinical Importance

Freezing samples at −80°C for more than 18 months might alter test results, leading to possible changes in serum to CSF ratio calculations and affecting the interpretation of results for clinical and research purposes.

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长期冷冻对诊断马原生动物髓脑炎间接荧光抗体效价的影响

长期冷冻储存会改变蛋白质的稳定性，从而影响间接荧光抗体试验（IFAT）滴度的准确测定，而间接荧光抗体试验（IFAT）滴度支持马原生动物髓脑炎的诊断。目的评价- 80℃长期保存对马血清和脑脊液中抗神经棘球蚴和大棘球蚴IFAT的影响。配对血清和脑脊液（n = 46）和仅血清（n = 25）样本。方法对储存6 ~ 12个月、13 ~ 18个月、19 ~ 24个月的标本进行前瞻性研究。比较各时间点抗体滴度，采用McNemar和Wilcoxon秩次检验进行统计分析。结果经长期冷冻保存19 ~ 24个月后，大鼠脑脊液的IFAT结果与新鲜检测时间点比较差异有统计学意义（p = 0.04），血清样品的IFAT结果差异无统计学意义（p = 0.04）。6-12、13-18、19-24个月后检测的血清或脑脊液样本与原始新鲜检测结果相比，无统计学差异。然而，在配对样本中，41%（46例中的19例）的血清与脑脊液比值≤64的临界值发生了变化。在- 80°C下冷冻样品超过18个月可能会改变检测结果，导致血清与脑脊液比值的计算可能发生变化，并影响临床和研究目的对结果的解释。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Veterinary Internal Medicine 农林科学-兽医学

CiteScore

4.50

自引率

11.50%

发文量

243

审稿时长

22 weeks

期刊介绍： The mission of the Journal of Veterinary Internal Medicine is to advance veterinary medical knowledge and improve the lives of animals by publication of authoritative scientific articles of animal diseases.