Experts Explain The Different COVID-19 Tests: Rapid Antigen Vs RT-PCR Test, Which Is Better?

Experts Explain The Different COVID-19 Tests: Rapid Antigen Vs RT-PCR Test, Which Is Better?

Both RT-PCR test and Rapid Antigen Test lookout for the virus in the sample and are used for the diagnosis of COVID-19
Coronavirus Outbreak, News
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Experts Explain The Different COVID-19 Tests: Rapid Antigen Vs RT-PCR Test, Which Is Better?COVID-19 testing: RT-PCR test is considered as the gold standard for testing
Highlights
  • RT-PCR test has a high specificity rate; gives less false positives
  • Only nasopharyngeal swabs are collected for Rapid Antigen Test
  • RAT has moderate sensitivity, can give false negative results for COVID-19

New Delhi: Testing for Coronavirus has been ramped up in India from 2.07 lakh tests on June 24 to over 4.08 lakh tests per day on July 28 and 6.19 lakh samples tested on August 4. Rapid Antigen Tests (RAT) has helped in a substantial increase in testing in the country and especially in the national capital Delhi. In a media briefing on August 4, ICMR Director General Dr Balram Bhargava informed that 25-30 per cent of the tests conducted are RAT. However, it’s a known fact that RAT can give a high number of false negatives. Recently, Delhi High Court pulled UP the AAP government for choosing Rapid Antigen Testing (RAT), as the primary test of COVID-19 infection over RT-PCR (Reverse transcription-polymerase chain reaction) which is considered as the gold standard for testing.

Also Read: Delhi’s Coronavirus Trends Number Show Positive Signs But Testing Strategy Raises Many Questions: Experts

NDTV spoke to experts to understand the two main kinds of tests for COVID-19 diagnosis – RT-PCR and RAT and their reliability.

According to Dr Navin Dang, founder of Dr Dang’s lab in Delhi, all the tests available in the market for testing of COVID-19 have their own pros and cons but RT-PCR remains the gold standard for testing. Explaining the process of RT-PCR test, Dr Dang said,

This is performed by taking swabs from nasal and oral tracts which are then put in viral transport medium and brought to the lab. It is processed under bio safety level 2 plus facilities; we do RNA (Ribonucleic acid) extraction to detect the presence of the virus.

RT-PCR test has a specificity rate (ability to identify those without the disease) of nearly 100 per cent whereas the sensitivity rate (ability to identify those with the disease) of about 67 per cent. This means, RT-PCR test will not give false positives but there are 30-35 per cent chances of getting false negatives. Explaining the reason behind the low sensitivity rate and why is RT-PCR test still considered the gold standard for testing, Dr Dang said,

There are three main reasons, one, the technology itself which we cannot consider as a limitation. Secondly, if the samples are not taken properly then the result can be a false negative. This is the reason we take both nasal and oral swabs. Ideally, samples should be collected by experts who are trained to go to the nasopharyngeal or oropharyngeal cavity. Thirdly, people are now seeing it as a preventive test which means they are getting the test done even in the absence of symptoms. The average incubation period of SARS-CoV-2 is 5.6 days so an individual will test positive only after six days of contracting the virus. Undergoing a COVID-19 test at the initial stage when the viral load is very low can give negative results. Also, there is no other test that has got better sensitivity.

Also Read: Coronavirus Explainer: 20 COVID-19 Related Terms And What These Mean

At the initial stage of the Coronavirus pandemic, RT-PCR test was priced at Rs. 4,500 but now the cost has been brought down to Rs. 2,500. It is still expensive and takes a day to give results.

Talking about the time consuming process, Dr Harsh Mahajan, Founder of Mahajan Imaging and Chairman of CARINGdx, said,

In RT-PCR you can put 96 samples at a time so one has to wait for the samples to reach the laboratory and then process them. Less than 96 samples can be processed but it will increase the cost of testing.

As far as Rapid Antigen Test (RAT) is concerned, it is gaining grounds and has led to a spike in the number of tests being conducted, as it is quick and cheap. Only nasopharyngeal swabs are collected by trained healthcare workers. RAT detects the presence of viral proteins (antigens – attributes of the virus) in a sample from the respiratory tract of a person. However, it is capable of giving more false negatives. Explaining the same, Dr Mahajan said,

RAT has moderate sensitivity (around 50 per cent) and high specificity which means if you test 100 COVID-19 patients, it will give positive results for only 50 of them.

Also Read: Coronavirus Outbreak Explained: What Is Antibody Test And What Role Does It Play In The Fight Against COVID-19?

According to the ICMR protocol, if RAT gives negative result and an individual has symptoms of ILI (influenza like illness), then he/she should undergo RT-PCR test.

Also, RAT is a point of care test which means it can be performed only in hospital settings rather than standalone testing labs. Elaborating on this, Dr Dang said,

Sanctity of the test that is from the time sample is taken and is processed, is about 1 hour so it cannot be done at any collection centre. It is not possible to collect, label, transport and process the sample within one hour, even if it is collected within three to four kms from the lab.

If RAT does not provide standardised testing and results, why is India conducting RAT? Answering the question, Dr Dang said,

RAT has its own advantages in the way it can be done on a mass level. The numbers of tests that are being performed are in thousands now. The tests are being performed even in community centres, Gurdwara and other places. But too much of reliability on rapid antigen tests which shows a lot of false negatives is a questionable thing and I think the government may have to reconsider it. Right now, the number of people asking for a test is high and the number of RT-PCR tests labs are being able to provide is not that great.

Explaining how a government should increase testing with RAT and at the same time ensure it doesn’t miss COVID-19 positive patients, global health expert Anant Bhan suggests a balance between RAT and RT-PCR test. He added,

If antigen tests are being used it needs to be backed by RT-PCR test and only then we can say that yes there has been a decrease in coronavirus cases in that particular area. If the numbers of both the tests are not matching then it is a serious issue and it may reflect a bad picture.

Mr Bhan recommends all states to ramp up testing by not only increasing the number of rapid antigen tests, but also backing it by RT-PCR tests.

Also Read: Coronavirus Crisis: Community Transmission Taking Place In India, Here’s What Experts Have To Say

NDTV – Dettol Banega Swasth India campaign is an extension of the five-year-old Banega Swachh India initiative helmed by Campaign Ambassador Amitabh Bachchan. It aims to spread awareness about critical health issues facing the country. In wake of the current COVID-19 pandemic, the need for WASH (WaterSanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign highlights the importance of nutrition and healthcare for women and children to prevent maternal and child mortality, fight malnutrition, stunting, wasting, anaemia and disease prevention through vaccines. Importance of programmes like Public Distribution System (PDS), Mid-day Meal Scheme, POSHAN Abhiyan and the role of Aganwadis and ASHA workers are also covered. Only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and become a Swasth or healthy India. The campaign will continue to cover issues like air pollutionwaste managementplastic banmanual scavenging and sanitation workers and menstrual hygiene

World

3,04,91,096Cases
87,62,381Active
2,07,76,975Recovered
9,51,740Deaths
Coronavirus has spread to 188 countries. The total confirmed cases worldwide are 3,04,91,096 and 9,51,740 have died; 87,62,381 are active cases and 2,07,76,975 have recovered as on September 19, 2020 at 3:48 am.

India

53,08,014 93337Cases
10,13,964 -3790Active
42,08,431 95880Recovered
85,619 1247Deaths
In India, there are 53,08,014 confirmed cases including 85,619 deaths. The number of active cases is 10,13,964 and 42,08,431 have recovered as on September 19, 2020 at 2:30 am.

State & District Details

State Cases Active Recovered Deaths
DistrictCases
Akola757
Aurangabad1974
Dhule228
Jalgaon1039
Mumbai45478
Mumbai Suburban5363
Nagpur692
Nashik1575
Palghar1421
Pune9920
Satara629
Solapur1291
Thane13660
Yavatmal150
Ahmednagar190
Amravati291
Beed54
Bhandara41
Buldhana88
Chandrapur32
Hingoli208
Jalna201
Kolhapur646
Latur139
Nanded176
Nandurbar42
Parbhani78
Raigad1462
Ratnagiri350
Sangli145
Gadchiroli42
gondia69
Osmanabad125
Sindhudurg114
Wardha11
Washim13

1167496 21656

301273

834432 22078

31791 440

DistrictCases
Chittoor319
Guntur511
Krishna557
Kurnool795
Sri Potti Sriramulu Nell*296
Anantapur428
East Godavari356
Prakasam104
Srikakulam183
Visakhapatnam103
West Godavari199
Y.S.R.205
Vizianagaram23

609558 8096

84423

519891 11803

5244 67

DistrictCases
Bengaluru Rural40
Bengaluru Urban529
Mysuru107
Bagalkote103
Ballari60
Belagavi337
Bidar219
Chikkaballapura149
Dakshina Kannada179
Dharwad61
Gadag45
Kalaburagi669
Mandya346
Tumakuru36
Uttara Kannada95
Vijayapura201
Chamarajanagara0
Chikkamagaluru19
Chitradurga14
Davangere204
Hassan205
Haveri24
Kodagu4
Kolar29
Koppal5
Raichur369
Ramanagara3
Shivamogga67
Udupi1176
Yadgir538

502982 8626

101148

394026 10949

7808 179

DistrictCases
North Goa57
South Goa69

27379 596

5730 118

21314 470

335 8

DistrictCases
Chengalpattu1314
Chennai23324
Kanchipuram503
Madurai322
Namakkal83
Ranipet133
Thanjavur130
Thiruvallur774
Thiruvarur67
Tiruppur116
Vellore71
Virudhunagar185
Ariyalur444
Coimbatore188
Cuddalore477
Dharmapuri15
Dindigul175
Erode75
Kallakurichi324
Kanniyakumari110
Karur88
Nagapattinam99
Perambalur133
Pudukkottai53
Ramanathapuram119
Salem258
Sivaganga46
Tenkasi103
The Nilgiris17
Theni129
Tiruchirappalli119
Tirunelveli433
Tirupathur45
Tiruvannamalai496
Tuticorin333
Villupuram509
Krishnagiri43

530908 5488

46506

475717 5525

8685 67

DistrictCases
Kannur357
Kottayam73
Alappuzha76
Idukki40
Kasaragod333
Kollam118
Kozhikode90
Malappuram119
Palakkad224
Pathanamthitta98
Thiruvananthapuram104
Thrissur106
Ernakulam60
Wayanad36

126381 4167

35795 1415

90085 2740

501 12

DistrictCases
Raipur46
Korba100
Balod41
Baloda Bazar85
Balrampur17
Bastar2
Bemetara21
Bijapur2
Bilaspur100
Dantewada0
Dhamtari6
Durg31
Gariyaband10
Janjgir-Champa56
Jashpur77
Kabirdham52
Kanker19
Kondagaon0
Korea39
Mahasamund54
Mungeli87
Narayanpur0
Raigarh47
Rajnandgaon52
Sukma0
Surajpur9
Surguja14

81617 3842

36580 544

44392 3281

645 17

DistrictCases
Hyderabad2475
MedchalMalkajgiri75
Ranga Reddy183
Suryapet87
Vikarabad40
Warangal Urban32
Adilabad22
Jagitial77
Jangoan8
Jayashankar Bhupalapally9
Jogulamba Gadwal40
Kamareddy11
Karimnagar17
Khammam26
Kumuram Bheem Asifabad8
Mahabubnagar30
Mancherial43
Medak11
Nalgonda33
Narayanpet3
Nirmal21
Nizamabad76
RajannaSircilla16
Sangareddy26
Bhadradri Kothagudem5
Mahabubabad10
Mulugu3
Nagarkurnool8
Peddapalli5
Siddipet7
Wanaparthy1
Warangal Rural4
YadadriBhuvanagiri40

169169 2123

30636

137508 2151

1025 9

DistrictCases
Baleshwar190
Bhadrak137
Jajapur322
Dhenkanal36
Kalahandi33
Kendrapara164
Khordha238
Koraput16
Sundargarh102
Anugul26
Balangir129
Bargarh16
Boudh34
Cuttack155
Deogarh33
Gajapati61
Ganjam581
Jagatsinghapur91
Jharsuguda8
Kandhamal28
Kendujhar34
Malkangiri20
Mayurbhanj73
Nabarangpur2
Nayagarh86
Nuapada69
Puri103
Rayagada2
Sambalpur16
Sonepur29

171341 4180

33092 66

137567 4101

682 13

DistrictCases
Barwani60
Bhopal1880
Dewas140
Dhar132
East Nimar266
Gwalior211
Indore3839
Jabalpur276
Ujjain799
Agar Malwa15
Alirajpur3
Betul35
Burhanpur351
Chhindwara16
Dindori29
Harda4
Hoshangabad37
Khargone196
Mandsaur112
Morena109
Raisen71
Ratlam51
Sagar228
Shajapur39
Shandol14
Sheopur26
Tikamgarh18
Vidisha37
Anuppur22
Ashoknagar13
Balaghat9
Bhind87
Chhatarpur35
Damoh26
Datia12
Guna8
Jhabua14
Katni3
Mandla15
Narsinghpur17
Neemuch319
Niwari0
Panna20
Rajgarh31
Rewa39
Satna24
Sehore12
Seoni2
Shivpuri15
Sidhi17
Singrauli13
Umaria10

100458 2552

21605

76952 2554

1901 24

DistrictCases
Ahmadabad17125
Anand107
Arvalli134
Banas Kantha147
Bhavnagar146
Gandhinagar410
PanchMahals107
Surat2311
Vadodara1555
Bharuch56
Botad55
Chhotaudepur37
Dang5
Dohad43
GirSomnath45
Jamnagar63
Kachchh99
Kheda98
Mahesana159
Mahisagar125
Narmada25
Naysari35
Patan105
Rajkot135
SabarKantha101
Surendranagar55
Tapi6
Valsad47
Amreli16
DevbhumiDwarka22
Junagadh31
Morbi4
Porbandar11

120336 1410

16076 101

100974 1293

3286 16

DistrictCases
Ajmer379
Banswara91
Bharatpur563
Jaipur2177
Jhalawar329
Jodhpur1748
Kota503
Nagaur500
Alwar90
Barmer34
Bhilwara250
Bikaner112
Chittorgarh188
Churu81
Dausa61
Dholpur60
Dungarpur374
Hanumangarh31
Jaisalmer53
Jhunjhunu64
Karauli17
Pali352
Rajsamand140
SawaiMadhopur26
Sikar231
Tonk171
Udaipur724
Baran59
Bundi5
Ganganagar8
Jalore164
Pratapgarh14
Sirohi130

111290 1817

17717 222

92265 1580

1308 15

DistrictCases
Faridabad867
Sonipat404
Ambala93
Bhiwani60
CharkiDadri43
Fatehabad38
Gurugram2950
Hisar98
Jhajjar114
Jind38
Kaithal48
Karnal104
Kurukshetra55
Nuh68
Palwal120
Panchkula39
Panipat78
Rohtak145
Sirsa50
Yamunanagar19
Mahendragarh47
Rewari56

106261 2488

21291 277

83878 2188

1092 23

DistrictCases
Agra933
Aligarh215
Amroha80
Bareilly17
Bijnor157
Bulandshahr166
Firozabad190
Gautam Buddha Nagar1119
Kanpur Nagar286
Lucknow386
Mathura129
Meerut504
Moradabad252
Muzaffarnagar117
Rae Bareli78
Rampur203
Saharanpur298
Sant Kabeer Nagar132
Varanasi243
Auraiya37
Ayodhya120
Azamgarh138
Baghpat68
Bahraich73
Balrampur49
Banda27
Basti214
Bhadohi60
Budaun23
Etah52
Etawah46
Ghaziabad794
Ghazipur159
Gonda59
Gorakhpur166
Hapur225
Hardoi49
Jalaun41
Jaunpur194
Jhansi41
Kannauj69
Kasganj16
Kaushambi6
Mainpuri46
Mau48
Mirzapur22
Pilibhit15
Pratapgarh15
Prayagraj30
Sambhal116
Shamli40
Shravasti23
Sitapur32
Sultanpur97
Unnao42
Ambedkar Nagar92
Amethi206
Ballia60
Barabanki168
Chandauli38
Chitrakoot4
Deoria143
Farrukhabad36
Fatehpur3
Hamirpur3
Hathras43
Kanpur Dehat4
Kheri72
Kushi Nagar67
Lalitpur3
Maharajganj85
Mahoba3
Shahjahanpur25
Siddharth Nagar159
Sonbhadra10

342788 6494

67825

270094 6806

4869 98

DistrictCases
Central4817
East2472
New Delhi3405
North3059
North East1914
North West5463
Shahdara1580
South2329
South East2446
South West2391
West4768

238828 4127

32250 529

201671 3568

4907 30

DistrictCases
Dhubri30
Goalpara19
Marigaon50
Baksa14
Barpeta28
Biswanath16
Bongaigaon12
Cachar80
Charaideo29
Chirang6
Darrang20
Dhemaji47
Dibrugarh61
Dima Hasao86
Golaghat203
Hailakandi57
Hojai89
Jorhat24
Kamrup42
Kamrup Metro276
KarbiAnglong13
Karimganj85
Kokrajhar37
Lakhimpur57
Majuli2
Nagaon143
Nalbari23
Sivasagar20
Sonitpur27
South SalmaraMancachar4
Tinsukia84
Udalguri28
West KarbiAnglong5

152858 2509

28631 423

123687 2074

540 12

DistrictCases
East District3
North District0
South District3
West District0

2303 29

422

1857 68

24 2

DistrictCases
Buxar134
Gaya115
Munger188
Patna279
Rohtas256
Arwal52
Aurangabad75
Banka134
Begusarai243
Bhagalpur266
Bhojpur103
Darbhanga143
Gopalganj123
Jehanabad178
Kaimur (bhabua)105
Lakhisarai72
Madhepura82
Madhubani199
Nalanda123
Nawada122
PurbiChamparan138
Purnia135
Saran101
Siwan139
Vaishali87
Araria68
Jamui47
Katihar175
Khagaria253
Kishanganj75
Muzaffarpur96
Pashchim Champaran57
Saharsa88
Samastipur139
Sheikhpura118
Sheohar20
Sitamarhi73
Supaul87

165218 1167

12609

151750 1710

859 4

DistrictCases
24 Paraganas North1031
24 Paraganas South281
Darjeeling97
Howrah1435
Jalpaiguri88
Kalimpong18
Kolkata2777
Maldah235
Medinipur East153
Medinipur West159
Hooghly604
Murshidabad125
Nadia139
Paschim Bardhaman70
Purba Bardhaman130
Alipurduar39
Bankura116
Birbhum206
Coochbehar210
Dinajpur Dakshin50
Dinajpur Uttar216
Jhargram9
Purulia66

218772 3192

24509 173

190021 2960

4242 59

DistrictCases
South Andamans33
Nicobars1
North And Middle Andaman1

3631 27

165

3414 36

52

DistrictCases
Pondicherry111
Karaikal2
Mahe4
Yanam0

21913 485

4736

16715 462

462 31

DistrictCases
Anjaw0
Changlang31
Dibang Valley0
East Kameng0
East Siang1
Kamle0
KraDaadi0
KurungKumey0
Leparada0
Lohit3
Longding0
Lower Dibang Valley0
Lower Siang0
Lower Subansiri0
Namsai2
PakkeKessang1
Papum Pare8
Shi Yomi0
Siang0
Tawang1
Tirap0
Upper Siang1
Upper Subansiri0
West Kameng0
West Siang1

7005 154

1886 15

5106 139

13

DistrictCases
Dimapur20
Kiphire3
Kohima7
Longleng0
Mokokchung0
Mon8
Peren2
Phek1
Tuensang3
Wokha0
Zunheboto0

5357 51

1213 20

4129 31

15

DistrictCases
Dadra And Nagar Haveli20

2859 28

218

2639 31

2

DistrictCases
Ranchi148
Bokaro16
Deoghar5
Dhanbad32
Garhwa80
Giridih19
Hazaribagh110
Jamtara2
Koderma58
Simdega48
Chatra1
Dumka5
East Singhbum170
Godda2
Gumla28
Khunti10
Latehar14
Lohardaga8
Pakur4
Palamu27
Ramgarh75
Sahebganj0
SaraikelaKharsawan20
West Singhbhum21

68578 1478

13924 221

54052 1245

602 12

DistrictCases
Gomati74
North Tripura14
Dhalai196
Khowai24
Sepahijala174
South Tripura53
Unakoti49
West Tripura45

21484 535

7107

14142 583

235 7

DistrictCases
Kargil77
LehLadakh43

3635 59

987 15

2600 42

48 2

DistrictCases
Anantnag395
Bandipora175
Shopian255
Srinagar300
Baramulla271
Budgam110
Ganderbal37
Jammu138
Kathua53
Kulgam295
Kupwara231
Rajouri39
Ramban151
Reasi26
Samba25
Udhampur155
Mirpur0
Muzaffarabad0
Doda27
Kishtwar10
Poonch35
Pulwama108

61041 1330

20770 531

39305 784

966 15

DistrictCases
Chamba29
Hamirpur117
Kangra105
Sirmaur11
Solan32
Una41
Bilaspur21
Kinnaur2
Kullu4
Lahaul And Spiti0
Mandi21
Shimla10

11622 432

4430 284

7081 135

111 13

DistrictCases
Jalandhar297
Ludhiana293
Patiala132
Amritsar485
Barnala25
Faridkot74
Firozepur50
Gurdaspur154
Hoshiarpur140
Kapurthala44
Mansa31
Moga65
Pathankot86
S.A.S Nagar137
Sangrur107
Shahid Bhagat Singh Nagar (Nawanshahr)99
Sri Muktsar Sahib71
Tarn Taran163
Bathinda60
Fatehgarh Sahib57
Fazilka53
Rupnagar (Ropar)74

92833 2801

21662 94

68463 2645

2708 62

DistrictCases
Haridwar94
Dehradun370
Nainital323
Almora71
Bageshwar31
Chamoli36
Champawat45
PauriGarhwal36
Pithoragarh43
Rudraprayag30
Tehri Garhwal110
Udam Singh Nagar83
Uttar Kashi24

38007 868

11293

26250 1285

464 4

DistrictCases
Bishnupur7
Chandel5
Churachandpur32
Imphal East10
Imphal West21
Jiribam3
Kakching2
Kamjong5
Kangpokpi26
Noney1
Pherzawl3
Senapati6
Tamenglong2
Tengnoupal9
Thoubal18
Ukhrul4

8607 177

1926 85

6629 91

52 1

DistrictCases
Chandigarh313

9506 250

2978

6415 353

113 4

DistrictCases
East Khasi Hills22
East Garo Hills0
East Jaintia Hills0
North Garo Hills1
Ribhoi0
South Garo Hills0
South West Garo Hills4
South West Khasi Hills0
West Garo Hills5
West Jaintia Hills1
West Khasi Hills1

4445 89

1976

2437 95

32 1

DistrictCases
Aizawl10
Champhai0
Hnahthial0
Khawzawl0
Kolasib11
Lawngtlai2
Lunglei2
Mamit8
Saiha0
Saitual1
Serchhip0

1548 14

575

973 24

0

DistrictCases
Lakshadweep District0

0

0

0

0

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