Evaluation and Clinical Validation of Guanidine-Based Inactivation Transport Medium for Preservation of SARS-CoV-2

Abstract

WHO declared the outbreak of COVID-19, caused by SARS-CoV-2, a pandemic in March 2020. More than 223 million cases and approximately 4.6 million deaths have been confirmed. Early diagnosis and immediate treatment became a priority during this pandemic. However, COVID-19 diagnostic testing resources are limited, especially early in the pandemic. Apart from being limited, the COVID-19 diagnostic tests using reverse transcription polymerase chain reaction (RT-PCR) have encountered storage, transportation, and safety issues. These problems are mainly experienced by developing poor countries, countries in the equatorial region, and archipelagic countries. VITPAD® is a guanidine-based inactivation transport medium (ITM) formulated to maintain the RNA quality of SARS-CoV-2 during transportation without cold chains. This study, conducted from September 2020 to March 2021, performed clinical validation of VITPAD® by comparing its performance with a globally commercially available ITM from the NEST brand. Its stability at room temperature, safety, and resistance at high temperatures was also tested using RT-PCR analysis. VITPAD® can reduce the infectious nature of the specimen, preserve the SARS-CoV-2 for 18 days at an ambient temperature, and resist high temperatures (40°C for 3 hours). A guanidine-based transport medium, such as VITPAD®, is compatible and recommended for RT-PCR-based molecular diagnosis of COVID-19.

Figure 1

Calculation of the internal control cycle threshold value (IC CT value) of the Sansure reagent. (a) Samples stored in VITPAD® ITM: mean IC CT value = 24.22, standard deviation = 2.476, and number of sample = 99; (b) samples stored in NEST ITM mean IC CT value = 23.80, standard deviation = 1.601, and number of sample = 98.

Figure 2

Receiver operating characteristic (ROC) curve. (a) Samples stored in VITPAD® ITM; (b) samples stored in NEST ITM.

Figure 3

CT value of target genes for the stability test at room temperature (±25°C). CT values of samples stored for 0 days, 4 days, 8 days, 12 days, and 18 days at room temperature (±25°C): (a) ORF1ab; (b) N-gene; and (c) E-gene. ns—not statistically significant. P-value >0.05 is considered not statistically significant.

Figure 4

CT value of target genes for the safety test. CT values of COVID-19 samples stored in VITPAD® ITM extracted with and without the lysis buffer: (a) ORF1ab; (b) N-gene; and (c) E-gene. ns—not statistically significant. P-value >0.05 is considered not statistically significant.

Figure 5

CT value of target genes for the resistance test. CT values of COVID-19 samples stored in VITPAD® ITM at room temperature (±25°C) and 40°C (for 3 hours): (a) ORF1ab; (b) N-gene; and (c) Internal control. ns—not statistically significant. P-value >0.05 is considered not statistically significant.