Table 1 Bimodality Coefficients and Hartigan’s Dip Test p-values of PCR Ct values by age and gender of patients and date of collection (values shaded in grey do not meet the threshold for Bimodality Coefficient or multimodality by Hartigan’s Dip Test).

From: Bimodal distribution pattern associated with the PCR cycle threshold (Ct) and implications in COVID-19 infections

 

Hartigan’s Dip Test

p-value

Bimodality coefficient

N1

N2

N1

N2

CDC PCR chemistry

All CDC (n = 5212)

Oct 2020–Sep 2021

< 0.001

< 0.001

0.5574

0.5725

 Age (Oct 2020–Sep 2021)

  65+ (n = 350)

0.0069

0.0030

0.5916

0.6079

  21–64 (n = 3739)

< 0.001

< 0.001

0.5631

0.5756

  < 21 (n = 1028)

< 0.001

< 0.001

0.5403

0.5602

  < 17 (n = 655)

< 0.001

< 0.001

0.5213

0.5402

  < 12 (n = 376)

0.0386

0.0293

0.5238

0.5392

  < 5 (n = 100)

0.0561

0.0107

0.5560

0.5783

 Gender (Oct 2020–Sep 2021)

  Female (n = 2338)

< 0.001

< 0.001

0.5557

0.5716

  Male (n = 2520)

< 0.001

< 0.001

0.5695

0.5842

 Date range

  Oct–Dec 2020 (n = 3149)

< 0.001

< 0.001

0.5497

0.5687

  Jan–Sep 2021 (n = 2063)

< 0.001

< 0.001

0.5719

0.5782

 

N

ORF1ab

N

ORF1ab

Fisher PCR chemistry

All Fisher (n = 8460)

Oct 2020–Sep 2021

< 0.001

< 0.001

0.5067

0.5267

Omicron (n = 878)*

0.0100

0.0201

0.4851

0.5156

  1. Numeric values that were below the statistic cut-off values are given in bold.
  2. *S gene target failure by Fisher multiplex PCR chemistry.
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