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Evaluation of the utility of testicular-only processing fluid for porcine reproductive and respiratory syndrome virus diagnostics and the effect of sample pooling on the test results Cover

Evaluation of the utility of testicular-only processing fluid for porcine reproductive and respiratory syndrome virus diagnostics and the effect of sample pooling on the test results

Journal of Veterinary Research
Volume 69 (2025): Issue 1 (March 2025)
By: ,   and    
Open Access
|Mar 2025
Figures & tables

Figures & Tables

Table 1.

Minimum, maximum and mean sample-to-positive ratio (S/P) values in the sera of female and male piglets and in testicular-only processing fluid (TOPF)

ParameterFemalesMales
Serum S/PSerum S/PTOPF S/P
Min.-0.018-0.032-0.030
Mean1.4121.2790.694
Max.3.5003.2202.610
Fig. 1.

Receiver operating curve for interpreting the sample-to-positive-control (S/P) ELISA results in testicular-only processing fluid (TOPF). Red line – male serum S/P (reference); green line – TOPF S/P

Table 2.

Sensitivity (SE), specificity (SP), negative and positive predictive values (NPV and PPV), and Cohen’s kappa coefficient (κ) obtained for testicular-only processing fluid using the ELISA manufacturer’s and receiver operating curve (ROC)-calculated cut-off values

ParameterELISA cut-off
Manufacturer’s (S/P ≥ 0.4)ROC-calculated (S/P ≥ 0.1)
SE (%)76.9686.47
SP (%)96.8496.31
NPV0.650.95
PPV0.980.91
κ0.650.86

1 S/P – sample-to-positive-control ratio

Table 3.

The effect of pooling one low-, one moderately- and one highly-positive testicular-only processing fluid (TOPF) sample (classified by sample-to-positive-control ratio (S/P)) with 4, 9, 19, 39 and 79 negative TOPF samples

DilutionLow-positive samplesModerately-positive samplesHighly-positive samples
S/PaCut-offS/PCut-offS/PCut-off
Manufacturer’s S/P ≥ 0.4Calculated S/P ≥ 0.1Manufacturer’s S/P ≥ 0.4Calculated S/P ≥ 0.1Manufacturer’s S/P ≥ 0.4Calculated S/P ≥ 0.1
Ndil0.951.872.18
1 : 50.35010.99111.3211
1 : 100.08000.51110.9911
1 : 200.05000.22010.5411
1 : 400.04000.17010.2401
1 : 800.02000.12010.1301
Ndil0.711.762.17
1 : 50.13010.96111.1611
1 : 100.08000.48111.0111
1 : 200.04000.26010.5211
1 : 400.02000.16010.3101
1 : 800.01000.11010.2201
Ndil0.601.692.16
1 : 50.11010.81111.1111
1 : 100.07000.41110.6211
1 : 200.03000.21010.3801
1 : 400.01000.1010.2501
1 : 800.00000.08000.1601
Ndil0.531.561.95
1 : 50.14010.75111.0111
1 : 100.07000.24010.6511
1 : 200.03000.19010.1501
1 : 400.00000.12010.201
1 : 800.00000.09000.1401
Correctly classified
1 : 50/44/44/44/44/44/4
1 : 100/40/43/44/44/44/4
1 : 200/40/40/44/42/44/4
1 : 400/40/40/44/40/44/4
1 : 800/40/40/42/40/44/4
Total0/204/207/2018/2010/2020/20

1 Ndil – not diluted

Table 4.

Minimum, maximum and mean threshold cycle (Ct) values in the serum of female and male piglets and in testicular-only processing fluid (TOPF)

ParameterFemalesMales
Serum CtSerum CtTOPF Ct
Min.19.7419.3621.27
Mean34.3934.1631.78
Max.44.5244.9344.93
Fig. 2.

Receiver operating curve for interpreting threshold cycle (Ct) results in testicular-only processing fluid (TOPF). Red line – male serum Ct (reference); green line – TOPF Ct

Table 5.

Sensitivity (SE), specificity (SP), negative and positive predictive values (NPV and PPV), and Cohen’s kappa coefficient (κ) obtained in real-time reverse-transcription (RT)-PCR for testicular-only processing fluid using the manufacturer’s and the receiver operating curve (ROC)-calculated cut-off values

Real-time RT-PCR cut-off
ParameterManufacturer’s (Ct < 45)ROC-calculated (Ct < 43.96)
SE (%)67.5767.57
SP (%)98.91100.00
NPV0.940.92
PPV0.921.00
κ0.740.77

1 Ct – cycle threshold

Table 6.

The effect of pooling one low-, one moderately- and one highly-positive testicular-only processing fluid (TOPF) sample with 9, 19, 39, 79, 159 and 319 negative TOPF samples

DilutionLow-positive samplesModerately-positive samplesHighly-positive samples
CtaCut-offCtCut-offCtCut-off
Manufacturer’s Ct < 45Calculated Ct < 43.96Manufacturer’s Ct < 45Calculated Ct < 43.96Manufacturer’s Ct < 45Calculated Ct < 43.96
Ndil38.34--34.09--21.9--
1 : 1039.161135.321126.8111
1 : 2040.881139.051127.7511
1 : 4000039.161129.0211
1 : 8000000029.921
1 : 16000000030.3211
1 : 32000000032.1811
Ndil43.7--34.16--22.62--
1 : 1000035.241125.0811
1 : 2000043.001125.4511
1 : 4000043.661127.0811
1 : 8000044.711027.8511
1 : 16000000028.0411
1 : 32000000029.4311
Ndil43.96--27.7--25.00--
1 : 1000029.481126.5911
1 : 2000030.951128.3811
1 : 4000033.361129.9411
1 : 8000033.661130.6311
1 : 16000043.471131.2811
1 : 32000043.781133.0511
Correctly classified
1 : 101/31/33/33/33/33/3
1 : 201/31/33/33/33/33/3
1 : 400/30/33/33/33/33/3
1 : 800/30/32/31/33/33/3
1 : 1600/30/31/31/33/33/3
1 : 3200/30/31/31/33/33/3
Total2/182/1813/1812/1818/1818/18

1 Ct – threshold cycle; Ndil – not diluted

DOI: https://doi.org/10.2478/jvetres-2025-0011 | Journal eISSN: 2450-8608 (formerly 2300-3235)
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Language: English
Page range: 7 - 16
Submitted on: Dec 19, 2024
Accepted on: Feb 25, 2025
Published on: Mar 1, 2025
Published by: National Veterinary Research Institute in Pulawy
In partnership with: Paradigm Publishing Services
Keywords:
diagnostic matrices,
porcine reproductive and respiratory syndrome,
processing fluid,
testicular-only processing fluid,
pigs
Related subjects:
Life sciences,
Molecular biology,
Microbiology and virology,
Life sciences, other,
Medicine,
Veterinary medicine

© 2025 Hanna Turlewicz-Podbielska, Arkadiusz Dors, Małgorzata Pomorska-Mól, published by National Veterinary Research Institute in Pulawy
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 69 (2025): Issue 1 (March 2025)
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