Reducing False Negative PCR Test for COVID-19

Bahreini, Fatemeh; Najafi, Rezvan; Amini, Razieh; Khazaei, Salman; Bashirian, Saeed

doi:10.21106/ijma.421

Cited by 23 publications

(25 citation statements)

References 11 publications

(14 reference statements)

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“…The possible reasons of PCR-test negativity could be false-negative results due to (i) inaccurate or low sensitivity test kits, (ii) incorrect nasopharyngeal swab technique, (iii) testing outside of the optimal time period (too early or too late) during low viral load and (iv) contamination of test samples [ 30 – 33 ]. Another potential reason might be a genetic diversity within species of SARS-CoV-2 [ 31 , 34 ]. In the reported studies, the PCR-test false negative rate ranged from 2 to 50% [ 35 , 36 ], however, in our data the PCR-test negative cases reached 94,5% among all PCR-tested cases.…”

Section: Discussionmentioning

confidence: 99%

SARS-CoV-2 PCR-positive and PCR-negative cases of pneumonia admitted to the hospital during the peak of COVID-19 pandemic: analysis of in-hospital and post-hospital mortality

et al. 2021

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Background During the spike of COVID-19 pandemic in Kazakhstan (June-2020), multiple SARS-CoV-2 PCR-test negative pneumonia cases with higher mortality were reported by media. We aimed to study the epidemiologic characteristics of hospitalized PCR-test positive and negative patients with analysis of in-hospital and post-hospital mortality. We also compare the respiratory disease characteristics between 2019 and 2020. Methods The study population consist of 17,691 (March–July-2020) and 4600 (March–July-2019) hospitalized patients with respiratory diseases (including COVID-19). The incidence rate, case-fatality rate and survival analysis for overall mortality (in-hospital and post-hospital) were assessed. Results The incidence and mortality rates for respiratory diseases were 4-fold and 11-fold higher in 2020 compared to 2019 (877.5 vs 228.2 and 11.2 vs 1.2 per 100,000 respectively). The PCR-positive cases (compared to PCR-negative) had 2-fold higher risk of overall mortality. We observed 24% higher risk of death in males compared to females and in older patients compared to younger ones. Patients residing in rural areas had 66% higher risk of death compared to city residents and being treated in a provisional hospital was associated with 1.9-fold increased mortality compared to those who were treated in infectious disease hospitals. Conclusion This is the first study from the Central Asia and Eurasia regions, evaluating the mortality of SARS-CoV-2 PCR-positive and PCR-negative respiratory system diseases during the peak of COVID-19 pandemic. We describe a higher mortality rate for PCR-test positive cases compared to PCR-test negative cases, for males compared to females, for elder patients compared to younger ones and for patients living in rural areas compared to city residents.

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Section: Discussionmentioning

confidence: 99%

SARS-CoV-2 PCR-positive and PCR-negative cases of pneumonia admitted to the hospital during the peak of COVID-19 pandemic: analysis of in-hospital and post-hospital mortality

et al. 2021

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“…The RT-PCR test for the COVID-19 diagnosis have several limitations, such as a considerable rate of false negative results [ 10 , 11 ], which are partially due to quality of sampling, the type of sample used, the viral load, and the time after infection at which sample is taken [ 34 ]. Despite this, it continues being the best technique to diagnose COVID-19 infection.…”

Section: Discussionmentioning

confidence: 99%

Higher Accuracy of Lung Ultrasound over Chest X-ray for Early Diagnosis of COVID-19 Pneumonia

Redondo

Rodríguez

Salud

et al. 2021

IJERPH

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Background: The COVID-19 pandemic rapidly strained healthcare systems worldwide. The reference standard for diagnosis is a positive reverse transcription polymerase chain reaction (RT-PCR) test, but results are not immediate and sensibility is variable. Aim: To evaluate the diagnostic accuracy of lung ultrasound compared to chest X-ray for COVID-19 pneumonia. Design and Setting: A retrospective analysis of symptomatic patients admitted into one primary care centre in Spain between March and September 2020. Method: Patients’ chest X-rays and lung ultrasounds were categorized as normal or pathologic. RT-PCR confirmed COVID-19 infection. Pathologic lung ultrasound images were further categorized as showing either local or diffuse interstitial disease. McNemar and Fisher tests were used to compare diagnostic accuracy. Results: Most of the 212 patients presented fever at admission, either as a standalone symptom (37.74% of patients) or together with others (72.17% of patients). The positive predictive value of the lung ultrasound was 90% for the diffuse interstitial pattern and 46.92% for local pattern. The lung ultrasound had a significantly higher sensitivity (82.75%) (p < 0.001), but lower specificity (71%) than the chest X-ray (54.02% and 86%, respectively) (p = 0.008) for identifying interstitial lung disease. Moreover, sensitivity of the lung ultrasound for severe interstitial disease was 100%, and was significantly higher than the chest X-ray (58.33%) (p = 0.002). Conclusion: The lung ultrasound is more accurate than the chest X-ray for identifying patients with COVID-19 pneumonia and it is especially useful for those presenting diffuse interstitial disease.

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“…There are several potential reasons for negative nasopharyngeal PCR tests including reduced viral load, transient viral dissemination or collection and storage errors. Research has shown a median false negative rate of COVID-19 nasopharyngeal RT-PCR of 38% on the day of symptom onset and maximum COVID-19 replication in the throat seen 5 days after symptom onset 10 , 11 .…”

Section: Discussionmentioning

confidence: 99%

COVID-19 Encephalitis with SARS-CoV-2 Detected in Cerebrospinal Fluid Presenting as a Stroke Mimic

Kelly¹,

Wood²,

McCausland

et al. 2021

Journal of Stroke and Cerebrovascular Diseases

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We report the case of a 35-year-old male with COVID-19 encephalitis presenting as a stroke mimic with sudden-onset expressive and receptive dysphasia, mild confusion and right arm incoordination. The patient received thrombolysis for a suspected ischaemic stroke, but later became febrile and SARS-CoV-2 was detected in cerebrospinal fluid. Electroencephalography demonstrated excess in slow waves, but neuroimaging was reported as normal. Respiratory symptoms were absent throughout and nasopharyngeal swab was negative for SARS-CoV-2. At the most recent follow-up, the patient had made a full neurological recovery. Clinicians should therefore consider testing for SARS-CoV-2 in CSF in patients who present with acute focal neurology, confusion and fever during the pandemic, even when there is no evidence of respiratory infection.

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Reducing False Negative PCR Test for COVID-19

Cited by 23 publications

References 11 publications

SARS-CoV-2 PCR-positive and PCR-negative cases of pneumonia admitted to the hospital during the peak of COVID-19 pandemic: analysis of in-hospital and post-hospital mortality

SARS-CoV-2 PCR-positive and PCR-negative cases of pneumonia admitted to the hospital during the peak of COVID-19 pandemic: analysis of in-hospital and post-hospital mortality

Higher Accuracy of Lung Ultrasound over Chest X-ray for Early Diagnosis of COVID-19 Pneumonia

COVID-19 Encephalitis with SARS-CoV-2 Detected in Cerebrospinal Fluid Presenting as a Stroke Mimic

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