Current practice and potential strategy in diagnosing COVID-19

Abstract

Objective:
To summarize the current practice and potential strategy in diagnosing coronavirus disease 2019 (COVID-19).

Materials and methods:
PubMed, Web of Science were systematically searched using terms including "COVID-19", "SARS-CoV-2" and "2019-nCoV". After removing duplicates, we then identified articles, letters and commentaries regarding diagnosing COVID-19.

Results:
Here we summarized relatively mature diagnostic methods like nuclear acid test and computed tomography. Besides, new aspects regarding these detection methods like suitable specimens for nuclear acid test, possible use of 18F-FDG PET/CT were also reported. Especially, we also presented several novel techniques for diagnosing COVID-19 like lung ultrasound.

Conclusions:
Chinese Clinical Guidance for COVID-19 Pneumonia Diagnosis and Treatment (7th edition) by National Health Commission is recommended to follow as it provides detailed diagnostic procedures using currently available tools. We suggest clinicians further explore the saliva's utility as a specimen for nuclear acid test and the use of lung ultrasound.

Full text

4548
Abstract. – OBJECTIVE: To summarize the
current practice and potential strategy in diag-
nosing coronavirus disease 2019 (COVID-19).
MATERIALS AND M ETHODS: PubMed, Web
of Science were systematically searched us-
ing terms including “COVID-19”, “SARS-CoV-2”
and “2019-nCoV”. After removing duplicates, we
then identied articles, letters and commentar-
ies regarding diagnosing COVID-19.
RE SU LT S : Here we summarized relatively ma-
ture diagnostic methods like nuclear acid test
and computed tomography. Besides, new aspects
regarding these detection methods like suitable
specimens for nuclear acid test, possible use of
18F-FDG PET/CT were also reported. Especially,
we also presented several novel techniques for di-
agnosing COVID-19 like lung ultrasound.
CONCLUSIONS: Chinese Clinical Guidance for
COVID-19 Pneumonia Diagnosis and Treatment
(7th edition) by National Health Commission is
recommended to follow as it provides detailed
diagnostic procedures using currently available
tools. We suggest clinicians further explore the
saliva’s utility as a specimen for nuclear acid test
and the use of lung ultrasound.
Key Words:
COVID-19, Diagnosis, Nuclear acid test, CT image,
IgM-IgG test.
Introduction
In December 2019, a new type of coronavirus
broke out in Wuhan and spread rapidly in China.
Later, other regions around the world soon report-
ed conrmed cases. In February 2020, the coro-
navirus study group of the International Com-
mittee on Taxonomy of Virus named the virus
Severe Acute Respiratory Syndrome Coronavirus
2 (SARS-CoV-2). As of March 16, 2020, the virus
has infected more than 80,000 people in China
and more than 90,000 in other countries, posing a
signicant threat to global public health security1.
SARS-CoV-2 is a single-stranded RNA virus
that belongs to the coronavirus β genus, struc-
tural proteins of which include S proteins, N
proteins, M proteins, and E proteins2. Its infecting
procedure shares a great similarity with SARS-
CoV2,3. By binding to the angiotensin-converting
enzyme 2 receptor on the outside membrane, the
virus gradually fuses into the host cell, causing
great damage to its original function.
This novel coronavirus is mainly transmitted
by aerosol like respiratory droplets generated
during coughing and sneezing by symptomatic
patients4. Caution is due here since asymptom-
atic patients in incubation period can also help
its transmission. Besides, the median incubation
period is 6.4 days, ranging from 2.1 days to 11.1
days5. This long period can cause great trouble in
containing this widely-spread pandemic. Failing
in restraining international transportation result-
ed in a surge in the number of suspected and
conrmed infections globally. To slow down its
spread and eventually contain it, accurate, rapid
and convenient screening and diagnostic methods
are of great signicance. Here we summarized
current practice and potential strategies in diag-
nosing COVID-19. This brief review may be of
help to clinicians who work in fever clinics or
perform screening in public areas.
Diagnosis
Clinical Features
At the early onset of this pandemic disease, a
report from Hubei initially summarized clinical
characteristics of 138 patients6. The authors found
that the most common symptoms were fever
(98.6%), fatigue (69.6%) and dry cough (59.4%)
and that elderly patients were more likely to prog-
ress into a severe stage and later be transferred
to intensive care units. Recently, Spiteri et al7
European Review for Medical and Pharmacological Sciences 2020; 24: 4548-4553
D.-Y. WAN1, X.-Y. LUO1, W. DONG2, Z.-W. ZHANG2
1The West China College of Medicine, Sichuan University, Chengdu, China
2Department of Intensive Care Medicine, West China Hospital, Sichuan University, Chengdu, China
D.-Y. Wan, X.-Y. Luo, and W. Do ng contributed equally in writing this article
Corresponding Author: Zhong-Wei Zhang, MD; e-mail: 716461751@qq.com
Current practice and potential strategy in
diagnosing COVID-19

Current practice and potential strategy in diagnosing COVID-19
4549
reported 20 cases of COVID-2019 in European
region, clinical manifestations of which share
some similarity with those of patients reported
from Wuhan. Fever was also found to be the most
common syndrome (n=20; 52.63%), followed by
cough (n=14; 36.84%), weakness (n=8; 21.05%)
and headache (n=6; 15.79%).
Laboratory Examination
Blood samples of suspected patients were rou-
tinely collected when they entered the hospital.
Indexes like white blood cell count and concen-
trations of C-reactive protein were then detected.
Lippi et al8 summarized several abnormal labora-
tory manifestations in COVID-19 infected peo-
ple. They recommended some possible indexes
for identifying suspected patients like increase in
CRP concentration and decrease in both leuko-
cytes and lymphocytes.
Nuclear Acid Test
Real time reverse-transcription poly chain re-
action (RT-PCR), the usual detection method for
common respiratory virus is also the primary
diagnostic means for 2019-nCoV9,10. However,
current positive rates of this test can vary greatly,
depending on types of the specimens and gene
fragments used.
Liu et al11 collected laboratory results of 4,880
cases from Jan 22 to Feb 14 in Renmin Hospital
of Wuhan University and found that the positive
rate of tests based on nucleocapsid protein se-
quence was 40.81%. But in Wang et al12, positive
rate of test targeting at open reading form 1ab
was reported to be 32.27%. As for different spec-
imens, things were even more complicated. Re-
cently, several researches investigated the biodis-
tribution of COVID-19 in different tissues. It was
found that, apart from excretion from respiratory
tract, the virus can also be detected in blood12,
tears13, oral uids14 and feces12,15,16. However, tests
on feces, blood, tears only have positive rates
measuring 29% (n=44), 1% (n=3) and 5% (n=1)
respectively, which cannot satisfy the needs for
accurate diagnosis12,13. Fortunately, saliva had a
remarkable performance in serving as samples.
In a diagnostic study, self-collected saliva of
91.7% of patients generated positive outcomes14.
Despite the high positive rates, procedures for
sampling saliva also involve less exposure chanc-
es, further guaranteeing clinicians’ safety. How-
ever, the limited cases involved restrain its usage
in practical settings. Thus, more relevant studies
are urgently needed.
One of the limitations of RT-PCR is the
time-consuming procedures involved in prac-
tical settings. Besides, its accuracy also needs
great improvements. To satisfy the growing
needs for a rapid and accurate NAT method for
COVID-19, several researches were done and
some of them generated rather promising out-
comes. Pfefferle et al17 described a new method,
cobas 6800 in detail. This integrated technol-
ogy performed on a high-throughput platform
allows less hands-on time while maintaining
fast and reliable results. In another study, Chan
et al18 illustrated three novel real-time RT-
PCR methods targeting at the RNA-dependent
RNA polymerase, envelope and nucleocapsid
genes from SARS-CoV-2. Of notice, this newly
developed assay, entitled COVID-2019-RdRp/
Hel, had a relatively lower limit of detection.
Combined with the fact that saliva contained
higher concentration of viral load14, this tech-
nique may signicantly reduce the false nega-
tive numbers and therefore limit the spread of
SARS-CoV-2. Apart from real time RT-PCR,
uorescence quantitative PCR (FQ-PCR) was
also proposed19. The report declared their expe-
rience of applying high-throughput sequencing
to further the inconclusive result generated by
the FQ-PCR.
Imaging Features
Computed Tomography
Though NAT is considered as the gold stan-
dard for COVID-19, abundant false positive
cases indicate that another complimentary tool
is needed. Computed tomography (CT) then
acts as such tool20 ,21. This method was basically
available in all sorts of medical institutions and
can generate outcomes rapidly. Bilateral ground
glass opacity was discovered in 98% of the
suspected cases in one study22. A more detailed
article reporting imaging features of different
disease stages was available recently23. Patchy
ground glass opacities in the peripheral areas
with partial consolidation in the center were
found in most of the common patients. Larger
areas of opacities and consolidations can be
discovered in severe patients. Of note, while one
lesion can be absorbed under correct medical
care, another novel lesion may soon appear in
another area. This phenomenon may inform us
of the necessity of repeated CT scanning for
closely evaluating disease progression.

D.-Y. Wan, X.-Y. Luo, W. Dong, Z.-W. Zhang
4550
To evaluate its accuracy in identifying pa-
tients with COVID-19 from suspected groups,
a report of 1,014 cases analyzed the correlation
of chest CT and NAT24. Researchers discovered
that the positive rate of CT test was much higher
than that of RT-PCR. Attention is needed when
clinicians interpret the results. 52% of 308 pa-
tients with negative RT-PCR but positive CT
results were not considered as conrmed cases
at last. That is to say, CT test is more likely to
generate false positive outcomes, which may
result in waste of medical resources. Worse still,
the error can hardly be estimated as suspected
patients with positive CT images may eventually
be affected in hospitals full of genuine patients.
Li et al20 specially demonstrated its defect in
differentiating COVID-19 from other viruses,
partially explaining the high false positive rate.
Besides, the accuracy of CT test depends greatly
on the radiologist. In the research by Ai et al24,
we may notice that an expert with 12 years of
experience was involved in the interpretation.
Lung Ultrasound
Apart from CT, lung ultrasound (US) was also
recommended recently25. It was once reported
to be superior to standard CT for evaluation of
pneumonia or respiratory distress syndrome26.
Peng et al27 performed lung US on 20 patients and
summarized ve main clinical ndings, including
thickening of the irregular pleural line. Besides, a
strong connection between ultrasonography nd-
ings and the disease stages was also reported.
This indicates its great use in dynamically mon-
itoring COVID-19 progression. Chinese Critical
Ultrasound Study Group published Critical-Ul-
trasound-based Recommendations on Severe
COVID -19 recently, in which lung US ndings
and relevant managements were described in
detail28.
18F- FDG PET/CT
18F-FDG PET/CT is a technology that can re-
ect changes in metabolic and functional states in
patients while observing pathogenic structures of
lesion sites. Qin et al29 reported clinical ndings
gained by 18F-FDG PET/CT. Ground-glass opaci-
ties showed a high tracer uptake of 18F-FDG. Be-
sides, the image rstly suggested that COVID-19
may cause lymphadenitis. However, a letter
against its use for diagnosis was published30. One
reason is the complex procedure needed would be
unpractical in most clinical settings, and the other
reason is the risk of disease spreading due to the
long period it takes.
Immunological Examinations
When combined together, detection methods
mentioned above are of help in identifying in-
fected patients in clinical settings. Nevertheless,
containing COVID-19 demands detection meth-
ods with large scale screening and eld detection
ability, neither of which is satised by etiological
detection or medical imaging technology.
Fortunately, a qualied method was success-
fully developed31. This novel technique uses lat-
eral ow immunoassay to detect IgM and IgG
antibodies against COVID-19 in human blood
samples simultaneously. Apart from the short
period, both sensitivity and specicity are also
remarkably high. It may suggest its potential use
as a diagnostic tool for rapid screening in public
area like airport, station, etc. Of notice, this tech-
nique can only tell whether the subject is infected
recently instead of the current conditions.
Prospects
The paragraph above illustrated the results ob-
tained from different specimens. Current samples
used in clinical settings are mainly nasal or pha-
ryngeal swabs, which usually generate positive
rates only measuring 40% or so11. However, we
may notice a study discovering that saliva showed
a remarkable performance in RT-PCR tests14. We
therefore recommend researchers to focus on this
utility and further explore the accuracy of NAT
detecting this specimen.
Notably, though blood and tears did not seem
to be of interest during diagnostic procedures,
they were reported to have a strong relationship
with specic clinical manifestations. Chen et
al32 reported a group of 58 cases. Patients with
detectable viral RNA in blood all gradually de-
veloped to a severe stage. The only sample of
tear that yielded positive results was collected
from a patient with conjunctivitis13. Nevertheless,
inherent defects in both studies resulted in these
unconvincing statements. More researches are
still needed for further illustrations.
Besides, lung US also seemed to be a prom-
ising technology available in most clinical set-
tings with ability to provide rapid outcomes25.
Of notice, this technique was also reported to

Current practice and potential strategy in diagnosing COVID-19
4551
have several limits27. For example, it can not
detect pathological changes that are deep in the
lung and therefore CT would still be of neces-
si t y. 18F-FDG PET/CT proposed by Qin et al29
may not be available in clinical use due to its
inherent defects. However, as it can reveal ab-
normal metabolic and functional manifestations
of COVID-19, it may serve as an investigation
tool for the time being.
As for the immunological test described, we
believe that it can be of great help in countries
with urgent needs for rapid screening to contain
the spread of COVID-19. Of note again, IgM-IgG
test is not able to test the current health condition
of patients, it can only inform us whether the pa-
tient was infected recently31. Thus, it should only
be used in eld detection to identify suspected or
conrmed patients and may not serve as an indi-
cator in discharge criteria.
We here recommend the Chinese Clinical
Guidance for COVID-19 Pneumonia Diagno-
sis and Treatment (7th edition) published by
National Health Commission, in which diag-
nosis procedures were given in great detail21.
Briey, the procedures can be divided into two
separate parts. To determine whether one is a
suspected patient, epidemiological history or
clinical symptoms are needed. Exposure history
involves any form of body contact with con-
rmed cases within 14 days and clinical features
include symptoms like fever, CT images with
signs mentioned above and laboratory examina-
tion showing decrease in both leukocytes and
lymphocytes. One with exposure history can be
considered as a suspected patient if any two of
the clinical features show up, but only when an
exposure-free patient represents all three clini-
cal features can he be suspected. Later, samples
from a suspected patient will run NAT and
serology test. When any of NAT and IgM-IgG
test generates positive result, he or she will be
conrmed and receive further treatments.
Lately, America, Australia, Iran and Italy all
reported a tremendous increase in conrmed
cases recently, among which Italy is now the
most serious region attacked by SARS-CoV-21.
There was a growing concern that COVID-19
will rapidly spread the European continent
among the public, which caused great panic
and inuenced the economic hugely33. Timely
and rm measures shall be taken to contain
the COVID-19 before it causes more damaging
results. To achieve this goal, timely diagnosis is
of great signicance. We hope this review will
help those who are ghting at the frontline and
the containment of this pandemic.
Conflict of Interest
The Authors declare that they have no conict of interests.
References
1) World HealtH organ ization. Novel Coronavirus
(COVID-19) Situation. [cited 2020 Mar 17]. Avail-
able from: https://experience.arcgis.com/experi-
ence/685d0ace521648f8a5beeeee1b9125cd.
2) lu r, zH ao X, li J, niu P, Yang B, Wu H, Wang W,
Song H, Huang B, zHu n, Bi Y, Ma X, zH an F, Wang
l, Hu t, zHou H, Hu z, zHou W, zHao l, CHen J,
Meng Y, Wang J, lin Y, Yuan J, Xie z, Ma J, liu WJ,
Wang d, Xu W, HolM eS eC, gao gF, Wu g, CHen
W, SHi W, tan W. Genomic characterisation and
epidemiology of 2019 novel coronavirus: implica-
tions for virus origins and receptor binding. Lan-
cet 2020; 395: 565-574.
3) CHen Y, guo Y, Pan Y, zH ao zJ. Structure analy-
sis of the receptor binding of 2019-nCoV. Bio-
chem Biophys Res Commun 2020 Feb 17.
pii: S0006-291X(20)30339-9. doi: 10.1016/j.
bbrc.2020.02.071. [Epub ahead of print].
4) rotHe C, SCH unk M, SotHM ann P, Bretzel g, FroeSCHl
g, WallrauCH C, ziMMer t, tHiel V, Janke C, gugge-
MoS W, SeilM aier M, droSten C, VollMar P, zWirgl-
Maier k, zange S, WolFel r, Hoel SCHer M. Transmis-
sion of 2019-nCoV infection from an asymptomat-
ic contact in Germany. N Engl J Med 2020; 382:
970-971.
5) BaCker Ja, klinkenBerg d, Wall inga J. Incubation
period of 2019 novel coronavirus (2019-nCoV) in-
fections among travellers from Wuhan, China, 20-
28 January 2020. Euro Surveill 2020; 25: 1-6.
6) Wang d, Hu B, Hu C, zHu F, liu X, zHang J, Wang
B, Xia ng H, CHeng z, Xiong Y, zHao Y, li Y, Wang
X, Peng z. Clinical characteristics of 138 hospital-
ized patients with 2019 novel coronavirus-infect-
ed pneumonia in Wuhan, China. JAMA 2020 Feb
7. doi: 10.1001/jama.2020.1585. [Epub ahead of
print].
7) SPiteri g, Fielding J, dierCke M, CaMPeSe C, enouF V,
gaYMard a, Bell a a, SognaMiglio P, Sierra MMJ, riu-
tort an, deMina Y V, MaHieu r, BroaS M, Bengner M,
Buda S, SCHilling J, Filleul l, lePoutre a, Saur a C,
MailleS a, leVY-BruHl d, Coignard B, Bernard SS, Be-
Hillil S, Van der WerF S, Va lette M, lina B, riCCardo F,
niCaStri e, CaSaS i, larr auri a, SaloM CaStell M, Po-
zo F, Ma kSYutoV ra, Martin C, Van rM, BoSSuYt n,
Siira l, Sane J, tegMark Wk, PalMeruS M, BroBerg ek,
Beaute J, JorgenSen P, Bundle n, PereYaSloV d, adl-
HoCH C, Puk kila J, PeBodY r, olSen S, CianCio BC. First
cases of Coronavirus Disease 2019 (COVID-19) in
the WHO European Region, 24 January to 21 Feb-
ruary 2020. Euro Surveill 2020; 25: 1-6.

D.-Y. Wan, X.-Y. Luo, W. Dong, Z.-W. Zhang
4552
8) liPPi g, PleB ani M. Laboratory abnormalities in
patients with COVID-2019 infection. Clin Chem
Lab Med 2020 Mar 3. pii: /j/cclm.ahead-of-
print/cclm-2020-0198/cclm-2020-0198.xml. doi:
10.1515/cclm-2020-0198. [Epub ahead of print].
9) CorMa n VM, landt o, kaiSer M, MolenkaMP r, Mei-
Jer a, CHu dkW, BleiCker t, Bru nink S, SCHneider J,
SCHMidt Ml, MulderS d, Ha agMa nS Bl, Van der Veer
B, Van den Brink S, WiJSM an l, goderSki g, roMet te
Jl, elliS J, zaMBon M, PeiriS M, gooSSenS H, reuSken
C, kooPM anS MPg, droSten C. Detection of 2019
novel coronavirus (2019-nCoV) by real-time RT-
PCR. Euro Surveill 2020; 25: 1-8.
10) Pang J, Wang MX, ang iYH, tan SHX, leWiS rF, CHen
Ji, gutierrez ra, gWee SXW, CHu a PeY, Yang Q,
ng XY, YaP rk, tan HY, teo YY, tan CC, Cook ar,
YaP JC, HSu lY. Potential rapid diagnostics, vac-
cine and therapeutics for 2019 novel coronavi-
rus (2019-nCoV): a systematic review. J Clin Med
2020; 9: 1-33.
11) li u r, Han H, liu F, lV z, Wu k, liu Y, Feng Y, zHu
C. Positive rate of RT-PCR detection of SARS-
CoV-2 infection in 4880 cases from one hospi-
tal in Wuhan, China, from Jan to Feb 2020. Clin
Chim Acta 2020 Mar 7. pii: S0009-8981(20)30112-
1. doi: 10.1016/j.cca.2020.03.009. [Epub ahead of
print].
12) Wang W, Xu Y, gao r, lu r, Han k, Wu g, tan
W. Detection of SARS-CoV-2 in different types
of clinical specimens. JAMA 2020 Mar 11. pii:
2762997. doi: 10.1001/jama.2020.3786. [Epub
ahead of print].
13) Xia J, tong J, liu M, SHen Y, guo d. Evaluation of
coronavirus in tears and conjunctival secretions
of patients with SARS-CoV-2 infection. J Med Vi-
rol 2020 Feb 26. doi: 10.1002/jmv.25725. [Epub
ahead of print].
14) to kk, tSang ot, CHik YYC, CH an kH, Wu tC, CHan
JMC, leung WS, CHik tS, CHo i CY, kandaMBY dH,
lung dC, taM ar, Poon rW, Fung aY, Hung iF,
CHeng VC, CHan JF, Yuen kY. Consistent detection
of 2019 novel coronavirus in saliva. Clin Infect
Dis 2020 Feb 12. pii: 5734265. doi: 10.1093/cid/
ciaa149. [Epub ahead of print].
15) tang a, tong zd, Wang Hl, da i YX, li kF, liu Jn,
Wu WJ, Yuan C, Yu Ml, li P, Yan JB. Detection of
novel coronavirus by RT-PCR in stool specimen
from asymptomatic child, China. Emerg Infect Dis
2020 Jun 17. doi: 10.3201/eid2606.200301. [Epub
ahead of print].
16) zHa ng J, Wang S, Xue Y. Fecal specimen diagno-
sis 2019 novel Coronavirus-infected pneumonia.
J Med Virol 2020 Mar 3. doi: 10.1002/jmv.25742.
[Epub ahead of print].
17) PFeFFerle S, reuCHer S, nor z d, lutgeHetMan n M.
Evaluation of a quantitative RT-PCR assay for
the detection of the emerging coronavirus SARS-
CoV-2 using a high throughput system. Euro Sur-
veill 2020; 25: 1-5.
18) CHa n JF, YiP CC, to kk, tang tH, Wong SC, leung
kH, Fung aY, ng aC, zou z, tSoi HW, CHoi gk,
taM ar, CHeng VC, CHan kH, tSang ot, Yuen kY.
Improved molecular diagnosis of COVID-19 by
the novel, highly sensitive and specic COVID-
19-RdRp/Hel real-time reverse transcription-poly-
merase chain reaction assay validated in vi-
tro and with clinical specimens. J Clin Microbi-
ol 2020 Mar 4. pii: JCM.00310-20. doi: 10.1128/
jcm.00310-20. [Epub ahead of print].
19) guan Wd, CHen lP, Ye F, Ye d, Wu Sg, zHou HX, He
JY, Ya ng Cg, zeng zQ, Wang Yt, li rF, du Ql, liang
Xl, Ma QH, Yang zF. High-throughput sequencing
for conrmation of suspected 2019-nCoV infec-
tion identied by uorescence quantitative poly-
merase chain reaction. Chin Med J (Engl) 2020
Mar 6. doi: 10.1097/cm9.0000000000000792.
[Epub ahead of print].
20) li Y, Xia l. Coronavirus Disease 2019 (COVID-19):
role of chest CT in diagnosis and management.
AJR Am J Roentgenol 2020 Mar 4. doi: 10.2214/
ajr.20.22954. [Epub ahead of print].
21) nationa l HealtH CoMMiSSion oF tHe PeoPle’S re-
PuBliC oF CH ina. Chinese Clinical Guidance for
COVID-19 Pneumonia Diagnosis and Treatment
(7th edition). [cited 2020 Mar 7]. Available from:
http://www.nhc.gov.cn/yzygj/s7653p/202003/
46c9294a7dfe4cef80dc7f5912eb1989/les/ce3e-
6945832a438eaae415350a8ce964.pdf.
22) Huang C, Wang Y, li X, ren l, zHao J, Hu Y, zHang
l, Fan g, Xu J, gu X, CHeng z, Yu t, Xia J, Wei Y, Wu
W, Xie X, Yin W, li H, liu M, Xiao Y, gao H, guo l,
Xie J, Wang g, Jiang r, gao z, Jin Q, Wang J, Cao
B. Clinical features of patients infected with 2019
novel coronavirus in Wuhan, China. Lancet 2020;
395: 497-506.
23) Xu YH, dong JH, an WM, lV XY, Yin XP, zHang
Jz, dong l, Ma X, zHang HJ, gao Bl. Clinical and
computed tomographic imaging features of novel
Coronavirus pneumonia caused by SARS-CoV-2.
J Infect 2020; 80: 394-400.
24) ai t, Yang z, Hou H, zHan C, CHen C, lV W, tao Q,
Sun z, Xi a l. Correlation of chest CT and RT-PCR
testing in Coronavirus disease 2019 (COVID-19)
in China: a report of 1014 cases. Radiology 2020
Feb 26: 200642. doi: 10.1148/radiol.2020200642.
[Epub ahead of print].
25) Poggiali e, daCreMa a, BaSton i d, tinelli V, deMiCHel e
e, Mateo rP, MarCiano t, SilVa M, VerCelli a, Mag-
naCaVal lo a. Can lung US help critical care clini-
cians in the early diagnosis of novel Coronavirus
(COVID-19) pneumonia? Radiology 2020 Mar 13.
doi: 10.1148/radiol.2020200847. [Epub ahead of
print].
26) MaY o PH, Co Pet ti r, Fell er- koP Ma n d, MatHiS g,
Maur Y e, Mongo di S, MoJol i F, Vol PiC elli g, za-
noBetti M. Thoracic ultrasonography: a narra-
tive review. Intensive Care Med 2019; 45: 1200-
1211.
27) Peng QY, Wang Xt, zHang ln; grouP CHineSe Crit-
iCal Care ultraSou nd StudY. Findings of lung ul-
trasonography of novel corona virus pneumonia
during the 2019–2020 epidemic. Intensive Care
Medicine 2020 Mar 12. doi: 10.1007/s00134-020-
05996-6. [Epub ahead of print].

Current practice and potential strategy in diagnosing COVID-19
4553
28) CCuSg, CHtCgrouP. Critical-ultrasound-based
recommendations on severe COVID-19. 2020
[cited 2020 Mar 17]. Available from: http://www.
ccusg.cn/newsinfo/372670.html.
29) Qin C, liu F, Yen tC, l an X. (18)F-FDG PET/CT nd-
ings of COVID-19: a series of four highly suspected
cases. Eur J Nucl Med Mol Imaging 2020 Feb 22.
pii: 10.1007/s00259 -020- 04734 -w. doi: 10.1007/
s00259-020- 04734-w. [Epub ahead of print].
30) Joo B B, WiWan itk it V. 18F-FDG PET/CT and
COVID-19. Eur J Nucl Med Mol Imaging 2020
Mar 12. pii: 10.1007/s00259-020-04762-6. doi:
10.1007/s00259-020-04762-6. [Epub ahead of
print].
31) li z, Yi Y, luo X, Xiong n, liu Y, li S, Sun r, Wang
Y, Hu B, CHen W, zHa ng Y, Wang J, Huang B, lin Y,
Yang J, Cai W, Wang X, CHeng J, CHen z, Sun k, Pan
W, zHan z, CHen l, Ye F. Development and clinical
application of a rapid IgM-IgG combined antibody
test for SARS-CoV-2 infection diagnosis. J Med
Virol 2020 Feb 27. doi: 10.1002/jmv.25727. [Epub
ahead of print].
32) CHen W, lan Y, Yuan X, deng X, li Y, Cai X, li l, He
r, tan Y, deng X, gao M, tang g, zHao l, Wang
J, Fan Q, Wen C, tong Y, tang Y, Hu F, li F, tang
X. Detectable 2019-nCoV viral RNA in blood is a
strong indicator for the further clinical severity.
Emerg Microbes Infect 2020; 9: 469-473.
33) aYitte Y Fk, aYitteY Mk, CHiWero nB, kaMaSa H JS, dz-
uVor C. Economic impacts of Wuhan 2019-nCoV
on China and the world. J Med Virol 2020; 92:
473-475.