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Pooling Five COVID-19 Samples May Not Lead To Much Loss Of Sensitivity Even For Low Viral Loads: ICMR Scientist

The Indian Council of Medical Research (ICMR) conducted a study to understand comparative analysis of pooled testing for five and 10 sample pools by RT-PCR at ten different laboratories conducting COVID-19 testing across the country

Pooling Five COVID-19 Samples May Not Lead To Much Loss Of Sensitivity Even For Low Viral Loads: ICMR Scientist
Highlights
  • The study has been published in the Indian Journal of Medical Research
  • Pooling 5 samples to detect coronavirus may be an acceptable strategy: ICMR
  • Pooling 10 samples could give considerably higher numbers of false negative

New Delhi: A study done by the Indian Council of Medical Research (ICMR) has revealed that pooling five samples to detect coronavirus by RT-PCR may be an acceptable strategy without much loss of sensitivity even for low viral loads, while with 10-sample pools there could be considerably higher numbers of false negatives. The study was done to understand comparative analysis of pooled testing for five- and 10-sample pools by RT-PCR at ten different laboratories conducting COVID-19 testing across the country.

The findings of the study have now been published in the latest edition of the Indian Journal of Medical Research (IJMR).

Also Read: Coronavirus Outbreak Explained: What Is Pool Testing And Can It Expedite COVID-19 Detection In The Country?

Dr Nivedita Gupta, a scientist at ICMR and author of the study, said that the laboratories are facing huge sample loads for COVID-19 diagnosis by RT-PCR.

The high sensitivity of optimized real-time RT-PCR assays makes pooled testing a potentially efficient strategy for resource utilization when positivity rates for particular regions or groups of individuals are low. We conducted a comparative analysis of pooled testing for 5- and 10-sample pools by real-time RT-PCR across 10 COVID-19 testing laboratories in India, she said.

At least ten virus research and diagnostic laboratories (VRDLs) testing COVID-19 by RT-PCR participated in this evaluation.

At each laboratory, 100 nasopharyngeal swab samples including 10 positive samples were used to create 5- and 10-sample pools with one positive sample in each pool. RNA extraction and real-time RT-PCR for SARS-CoV-2-specific E gene targets were performed for individual positive samples as well as pooled samples, Dr Gupta said.

The scientist said that concordance between individual sample testing and testing in the 5- or 10-sample pools was calculated and the variation across sites and by sample cycle threshold (Ct ) values was analyzed.

Results from this multi-site assessment suggest that pooling five samples for SARS-CoV-2 detection by RT-PCR may be an acceptable strategy without much loss of sensitivity even for low viral loads, while with 10-sample pools, there may be considerably higher numbers of false negatives. However, testing laboratories should perform validations with the specific RNA extraction and RT-PCR kits in use at their centres before initiating pooled testing, she said.

Also Read: ‘On-Demand’ COVID-19 Testing For All Individuals, No Delays In Emergency Procedure Due To Lack Of Testing: Health Ministry

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.) 

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World

26,10,35,501Cases
22,18,42,204Active
3,39,98,278Recovered
51,95,019Deaths
Coronavirus has spread to 196 countries. The total confirmed cases worldwide are 26,10,35,501 and 51,95,019 have died; 22,18,42,204 are active cases and 3,39,98,278 have recovered as on November 28, 2021 at 3:39 am.

India

3,45,72,523 8,774Cases
1,05,6911,328Active
3,39,98,278 9,481Recovered
4,68,554 621Deaths
In India, there are 3,45,72,523 confirmed cases including 4,68,554 deaths. The number of active cases is 1,05,691 and 3,39,98,278 have recovered as on November 28, 2021 at 2:30 am.

State Details

State Cases Active Recovered Deaths
Maharashtra

66,33,612 507

11,905 248

64,80,799 738

1,40,908 17

Kerala

51,29,359 4,741

49,152 957

50,40,528 5,144

39,679 554

Karnataka

29,95,285 322

6,783 143

29,50,306 176

38,196 3

Tamil Nadu

27,24,731 740

8,382 36

26,79,895 765

36,454 11

Andhra Pradesh

20,72,446 248

2,158 5

20,55,856 253

14,432

Uttar Pradesh

17,10,373 5

86 5

16,87,377 9

22,910 1

West Bengal

16,14,152 701

7,820 27

15,86,882 717

19,450 11

Delhi

14,40,834 27

290 11

14,15,448 37

25,096 1

Odisha

10,48,492 264

2,222 6

10,37,864 255

8,406 3

Chhattisgarh

10,06,733 27

326 7

9,92,814 20

13,593

Rajasthan

9,54,741 26

187 13

9,45,599 13

8,955

Gujarat

8,27,382 28

291 17

8,16,999 45

10,092

Madhya Pradesh

7,93,120 23

112 9

7,82,480 14

10,528

Haryana

7,71,654 11

159 1

7,61,441 10

10,054

Bihar

7,26,212 3

39 6

7,16,510 9

9,663

Telangana

6,75,479 160

3,545 11

6,67,946 148

3,988 1

Assam

6,16,435 123

2,720 71

6,07,624 189

6,091 5

Punjab

6,03,190 17

313 22

5,86,284 39

16,593

Jharkhand

3,49,216 20

109 0

3,43,967 20

5,140

Uttarakhand

3,44,183 14

150 6

3,36,626 8

7,407

Jammu And Kashmir

3,36,386 149

1,724 5

3,30,189 141

4,473 3

Himachal Pradesh

2,26,941 82

809 18

2,22,287 97

3,845 3

Goa

1,78,839 40

275 9

1,75,183 31

3,381

Mizoram

1,34,279 358

4,117 110

1,29,672 466

490 2

Puducherry

1,28,860 35

326 5

1,26,662 30

1,872

Manipur

1,25,117 19

673 1

1,22,474 18

1,970 2

Tripura

84,784 13

89 9

83,874 3

821 1

Meghalaya

84,414 20

308 27

82,635 44

1,471 3

Chandigarh

65,443 5

52 4

64,571 1

820

Arunachal Pradesh

55,269 9

37 4

54,952 5

280

Sikkim

32,211 4

114 5

31,694 9

403

Nagaland

32,100 4

135 1

31,269 5

696

Ladakh

21,494 27

249 6

21,032 21

213

Dadra And Nagar Haveli

10,683

1 0

10,678

4

Lakshadweep

10,394

28 1

10,315 1

51

Andaman And Nicobar Islands

7,680 2

5 2

7,546

129

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