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https://doi.org/10.11613/BM.2020.030401

Rate of re-positive RT-PCR test among patients recovered from COVID-19

Parham Habibzadeh ; Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
Mohammad M. Sajadi ; Institute of Human Virology, University of Maryland School of Medicine, Baltimore, United States of America
Amir Emami ; Burn and Wound Healing Research Center, Microbiology Department, Shiraz University of Medical Sciences, Shiraz, Iran
Mohammad Hossein Karimi ; Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Mahboobeh Yadollahie ; R&D Headquarters, Petroleum Industry Health Organization, Shiraz, Iran
Maryam Kucheki ; R&D Headquarters, Petroleum Industry Health Organization, Shiraz, Iran
Sahar Akbarpoor ; Department of Nursing, Larestan University of Medical Sciences, Larestan, Iran
Farrokh Habibzadeh ; R&D Headquarters, Petroleum Industry Health Organization, Shiraz, Iran

Puni tekst: engleski, pdf (54 KB) str. 355-356 preuzimanja: 23* citiraj
APA 6th Edition
Habibzadeh, P., Sajadi, M.M., Emami, A., Karimi, M.H., Yadollahie, M., Kucheki, M., ... Habibzadeh, F. (2020). Rate of re-positive RT-PCR test among patients recovered from COVID-19. Biochemia Medica, 30 (3), 355-356. https://doi.org/10.11613/BM.2020.030401
MLA 8th Edition
Habibzadeh, Parham, et al. "Rate of re-positive RT-PCR test among patients recovered from COVID-19." Biochemia Medica, vol. 30, br. 3, 2020, str. 355-356. https://doi.org/10.11613/BM.2020.030401. Citirano 02.12.2020.
Chicago 17th Edition
Habibzadeh, Parham, Mohammad M. Sajadi, Amir Emami, Mohammad Hossein Karimi, Mahboobeh Yadollahie, Maryam Kucheki, Sahar Akbarpoor i Farrokh Habibzadeh. "Rate of re-positive RT-PCR test among patients recovered from COVID-19." Biochemia Medica 30, br. 3 (2020): 355-356. https://doi.org/10.11613/BM.2020.030401
Harvard
Habibzadeh, P., et al. (2020). 'Rate of re-positive RT-PCR test among patients recovered from COVID-19', Biochemia Medica, 30(3), str. 355-356. https://doi.org/10.11613/BM.2020.030401
Vancouver
Habibzadeh P, Sajadi MM, Emami A, Karimi MH, Yadollahie M, Kucheki M i sur. Rate of re-positive RT-PCR test among patients recovered from COVID-19. Biochemia Medica [Internet]. 2020 [pristupljeno 02.12.2020.];30(3):355-356. https://doi.org/10.11613/BM.2020.030401
IEEE
P. Habibzadeh, et al., "Rate of re-positive RT-PCR test among patients recovered from COVID-19", Biochemia Medica, vol.30, br. 3, str. 355-356, 2020. [Online]. https://doi.org/10.11613/BM.2020.030401

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Ključne riječi
COVID-19; RT-PCR; laboratory test

Hrčak ID: 244713

URI
https://hrcak.srce.hr/244713

▼ Article Information


Reverse transcription polymerase chain reaction (RT-PCR) test is the most important laboratory test we currently rely on for the diagnosis of Coronavirus disease 2019 (COVID-19). There is no effective treatment or vaccine for COVID-19 (1). One option proposed to save lives is to use convalescent plasma obtained from recovered patients (2). There are reports that recovered patients may carry the whole virus and/or viral ribonucleic acid (RNA) (RT-PCR-positive) for long periods (3, 4).

Recently, health care officials in Larestan (Iran) decided to use the convalescent plasma to treat newly infected patients. They asked 35 patients with confirmed COVID-19 who had been hospitalized in Larestan Hospital during March 22 to March 26, 2020, to donate plasma. The diagnosis was made by RT-PCR according to a method described earlier (5). The RNA was extracted from nasopharyngeal swabs (Invitrogen ChargeSwitch Total RNA Cell Kit, Invitrogen Co, USA). The assay tested the E and RdRP genes (5). Both internal and negative controls were performed for tests. Thirteen of the 35 invited patients did agree to donate. They were thus re-tested with RT-PCR (using the same method) to determine if they were RT-PCR-negative. The study protocol was approved by the Petroleum Industry Health Organization Institutional Review Board.

Reverse transcription polymerase chain reaction test was positive in 9 (5 male, 4 female) of 13 recovered patients. They had a median age of 52 (interquartile range (IQR) 30 to 56) years. They presented mostly with cough, fever, malaise, and dyspnoea. On admission, 6 had abnormal findings in their chest and mediastinal unenhanced spiral computed tomography, including ground-glass opacities with or without consolidation; 4 had a positive C-reactive protein test; and 5 had 1 or 2 underlying medical conditions, most commonly hypertension (4 of 5). The disease severity was mild to moderate. The patients were hospitalized for a median of 5 (IQR 3 to 10) days. During hospitalization, they received osteltamivir (75 mg taken orally every 12 hours) and/or lopinavir/ritonavir (400/100 mg taken orally every 12 hours). They were discharged home when their symptoms resolved completely. Other laboratory parameters measured at the time of admission were within normal limits (Table 1). The second RT-PCR test was found positive in these patients after a median of 29 (range 22 to 54) days after initiation of their symptoms/illness and 18 (range 15 to 48) days after complete resolution of their symptoms.

Table 1 Baseline characteristics at hospital admission in 9 studied patients
ParameterMedian (IQR)
Body mass index (kg/m2)26.5 (22.8–29.0)
Haemoglobin (g/L)141 (129–168)
White blood cell count (x109/L)4.4 (3.9–5.3)
Absolute lymphocyte count (x109/L)1.77 (1.38–2.17)
Platelet (x109/L)172 (129–201)
Serum creatinine (μmol/L)88 (88–115)
Serum sodium (mmol/L)143 (139–145)
Serum potassium (mmol/L)3.5 (3.3–4.0)
Serum bicarbonate (mmol/L)23.8 (22.7–25.4)
Arterial pH7.39 (7.34–7.42)
Arterial pCO2 (kPa)5.5 (5.1–5.9)
IQR – interquartile range.

Observing 9 positive RT-PCR tests in 13 recovered patients after a median of 18 days of complete resolution of their symptoms – a positive rate of almost 70% – is very high. Even if we assume that all the remaining invited (but unattended) 22 recovered patients would have tested negative, the rate was still high – 26% (95% confidence interval (CI): 11% to 41%). Considering the low sensitivity (high false-negative rate) of RT-PCR test for the diagnosis of COVID-19 in nasopharyngeal samples, this rate would clearly be an underestimation (6). On account of the low sample size studied, the results might be considered trivial, at the first glance; however, even the lower limit of the 95% CI of the rate, 11%, is unacceptably high and potentially dangerous.

This high RT-PCR re-positive rate would have serious health implications in the world and might even change our strategies to tackle with the current pandemic. These patients, although asymptomatic, can potentially spread the virus after more than 2 weeks (even 48 days) of complete resolution of their symptoms. It is, however, worth to note that RT-PCR does not discriminate between intact whole virus and viral RNA. Therefore, a positive test does not necessarily imply an active infection or ability to transmit infection. This underlines the importance of developing tests to detect active viral replication and employing an active surveillance for identifying those infected with the virus, even asymptomatic people.

Notes

[1] Conflicts of interest None declared.

References

1 

Habibzadeh P, Stoneman EK. The Novel Coronavirus: A Bird’s Eye View. Int J Occup Environ Med. 2020 April;11:65–71. DOI: http://dx.doi.org/10.15171/ijoem.2020.1921 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/32020915

2 

Rubin R. Testing an Old Therapy Against a New Disease: Convalescent Plasma for COVID-19. JAMA. 2020;323:2114–7. DOI: http://dx.doi.org/10.1001/jama.2020.7456 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/32352484

3 

Lan L, Xu D, Ye G, Xia C, Wang S, Li Y, et al. Positive RT-PCR Test Results in Patients Recovered From COVID-19. JAMA. 2020;323:1502–3. DOI: http://dx.doi.org/10.1001/jama.2020.2783 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/32105304

4 

Korea Centers for Disease Control and Prevention. Findings from investigation and analysis of re-positive cases 2020. Available at: https://www.cdc.go.kr/board/board.es?mid=a30402000000&bid=0030. Accessed June 9th 2020.

5 

Corman VM, Landt O, Kaiser M, Molenkamp R, Meijer A, Chu DK, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. Euro Surveill. 2020;25:2000045. DOI: http://dx.doi.org/10.2807/1560-7917.ES.2020.25.3.2000045 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/31992387

6 

Kucirka LM, Lauer SA, Laeyendecker O, Boon D, Lessler J. Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction-Based SARS-CoV-2 Tests by Time Since Exposure. Ann Intern Med. 2020;•••:M20–1495. DOI: http://dx.doi.org/10.7326/M20-1495 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/32422057


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