Utilidad de la prueba de reacción en cadena de la polimerasa preoperatoria durante la pandemia por SARS-CoV-2: el desafío de la incidencia cambiante / Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence

Antecedentes y objetivo: La alta transmisibilidad de la infección por SARS CoV2 ha obligado a los sistemas de salud mundiales a arbitrar medidas para evitar su expansión. En España, el consenso alcanzado entre diferentes sociedades científicas recomienda la realización de la prueba de reacción en cadena de la polimerasa (PCR) como cribado preoperatorio de portadores asintomáticos. Nos propusimos evaluar el rendimiento de la PCR preoperatoria para detectar portadores asintomáticos. Material y métodos: Estudio observacional realizado en un hospital de tercer nivel. Comparamos los resultados de la prueba de PCR en tiempo real (RT-PCR) realizada en una cohorte de pacientes quirúrgicos de nuestra área asistencial con los resultados que hubiéramos esperado asumiendo los datos epidemiológicos publicados por las oficinas gubernamentales. Resultados: No registramos resultados positivos en las 2722 RT-PCR realizadas en nuestra área entre las semanas epidemiológicas 18 a 21, lo que implica una incidencia acumulada de nuevos casos tendente a cero. Asumiendo los datos epidemiológicos publicados, la proyección probabilística de individuos asintomáticos varió de 0.27 * 10e-4 (datos oficiales de nuevos casos diagnosticados por PCR) a 4.69 * 10e-4 si asumimos casos confirmados por IgG en nuestra provincia. Suponiendo una sensibilidad de RT-PCR del 95%, para obtener un resultado positivo, deberíamos realizar 38,461 y 2,028 pruebas respectivamente. Conclusiones: En escenarios de muy baja prevalencia y a pesar de su alta sensibilidad, la detección preoperatoria de portadores asintomáticos mediante de RT-PCR es de una efectividad cuestionable. Nuestros hallazgos evidencian la dificultad de establecer modelos predictivos fiables en el contexto de epidemias de evolución rápida, como la pandemia de SARS CoV2.(AU)

Introduction: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. Methods: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. Results: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27*10e -4 (according to official data of new cases diagnosed by PCR) to 4.69*10e -4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. Conclusions: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.(AU)

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27 × 10e-4 (according to official data of new cases diagnosed by PCR) to 4.69 × 10e-4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence. / Utilidad de la prueba de reacción en cadena de la polimerasa preoperatoria durante la pandemia por SARS-CoV-2: el desafío de la incidencia cambiante.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27*10e -4 (according to official data of new cases diagnosed by PCR) to 4.69*10e -4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.