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EMERGENCY USE AUTHORIZATION (EUA) SUMMARY
COVID-19 RT-PCR TEST
(LABORATORY CORPORATION OF AMERICA)
For In vitro Diagnostic Use Rx Only For use under Emergency Use Authorization (EUA) only
(The COVID-19 RT-PCR Test (Labcorp Laboratory Test Number: 139900) will be performed at the Center for Esoteric Testing in Burlington, North Carolina, or other laboratories designated by Labcorp that are also certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. §263a, and meet the requirements to perform high complexity tests, as described in the laboratory procedures that were reviewed by the FDA under this EUA.)
INTENDED USE
The COVID-19 RT-PCR Test is a real-time reverse transcription polymerase chain reaction (rRT-PCR) test for the qualitative detection of nucleic acid from SARS-CoV- in upper and lower respiratory specimens (nasopharyngeal or oropharyngeal swabs, sputum, lower respiratory tract aspirates, bronchoalveolar lavage, and nasopharyngeal wash/aspirate) collected from individuals suspected of COVID-19 by their healthcare provider (HCP), as well as upper respiratory specimens (nasopharyngeal or oropharyngeal swabs, anterior nasal swabs, or mid-turbinate swabs) collected from any individual, including individuals without symptoms or other reasons to suspect COVID-
This test is also for use with individual anterior nasal swab specimens from individuals age 18 years and older (self-collected), 14 years and older (self-collected under adult supervision), or 2 years and older (collected with adult assistance) using the Labcorp At Home COVID-19 Test Home Collection Kit when directly ordered by an HCP.
The COVID-19 RT-PCR Test is also for the qualitative detection of nucleic acid from the SARS-CoV-2 in pooled samples, using a matrix pooling strategy (i.e., group pooling strategy), containing up to five individual upper respiratory swab specimens (nasopharyngeal, mid-turbinate, anterior nasal or oropharyngeal swabs collected using individual vials containing transport media) per pool and 25 specimens per matrix. Anterior nasal swab specimens are collected in individual vials containing transport media either under observation by an HCP or self-collected using a home collection kit authorized for use with this test.^1 Negative results from pooled testing should not be
(^1) Home collection kits currently authorized for use with this test include the Labcorp At
Home COVID-19 Test Home Collection Kit and the Pixel by LabCorp COVID-19 Test Home Collection Kit. Please note that Labcorp, authorized laboratories, and authorized distributors must follow the terms and conditions set forth in EUA 203057 concerning specimens collected using the Pixel by LabCorp COVID-19 Test Home Collection Kit.
treated as definitive. If a patient’s clinical signs and symptoms are inconsistent with a negative result or results are necessary for patient management, then the patient should be considered for individual testing. Specimens included in pools where the positive sample cannot be identified using the matrix must be tested individually prior to reporting a result. Specimens with low viral loads may not be detected in sample pools due to the decreased sensitivity of pooled testing.
Testing is limited to the Center for Esoteric Testing, Burlington, NC, or other laboratories designated by Labcorp that are also certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. §263a, and meet the requirements to perform high complexity tests.
Results are for the identification of SARS-CoV-2 RNA. The SARS-CoV-2 RNA is generally detectable in respiratory specimens during the acute phase of infection. Positive results are indicative of the presence of SARS-CoV-2 RNA; clinical correlation with patient history and other diagnostic information is necessary to determine patient infection status. Positive results do not rule out bacterial infection or co-infection with other viruses. The agent detected may not be the definite cause of disease. Laboratories within the United States and its territories are required to report all results to the appropriate public health authorities.
Negative results do not preclude SARS-CoV-2 infection and should not be used as the sole basis for patient management decisions. Negative results must be combined with clinical observations, patient history, and epidemiological information.
Testing with the COVID-19 RT-PCR Test is intended for use by trained clinical laboratory personnel specifically instructed and trained in the techniques of real-time PCR and in vitro diagnostic procedures. The COVID-19 RT-PCR Test is only for use under the Food and Drug Administration’s Emergency Use Authorization.
DEVICE DESCRIPTION AND TEST PRINCIPLE
The Labcorp At Home COVID-19 Test Home Collection Kit will be dispensed to patients when prescribed by their physician using the Labcorp provider interface to order diagnostic tests. Once the physician order is placed, Labcorp will mail the home collection kit to the patient, who will perform the sample collection and mail it back to Labcorp. Labcorp will then report test results back to the ordering physician and to the patient via the Labcorp patient portal.
The Labcorp At Home COVID-19 Test Home Collection Kit is composed of a shipping box, pre-labeled return envelope, directions, specimen collection materials (nasal swab and saline tube), and the specimen biohazard bag with absorbent pad. Instructions are included in the kit to direct the home users on how to appropriately collect the nasal swab specimen and place it in the saline transport tube, how to properly package the specimen and how to mail the specimen back to the laboratory using the pre-labeled FedEx return envelope.
Matrix Based Pooling Strategies Increase Throughput Without Requiring Retesting. Green - <1 positive per matrix at indicated prevalence, red - >1 positive per matrix at indicated prevalence
INSTRUMENTS USED WITH TEST
The COVID-19 RT-PCR test is to be used with the Roche MagNA Pure-96 (MP96) using MagNA Pure 96 DNA and Viral NA Small Volume Kit and Applied Biosystems QuantStudio7 Flex (QS7) instrument with software version 1.3 in a singleplex format. The COVID-19 RT-PCR test can also be used with the CERES Nanosciences Nanotrap Virus Capture Kit.
Pooling is conducted on the Tecan Evo 200 liquid handling instrument. All pooling of samples is performed before sample extraction.
When the COVID-19 RT-PCR test is multiplexed into a single reaction, it is automated on the Hamilton Microlab star liquid handler and uses two extraction methods: 1) Thermo Fisher MagMAX Viral/Pathogen Nucleic Acid Isolation Kit on the Thermo Fisher KingFisher Flex instrument; 2) MagNA Pure 96 DNA and Viral NA Small Volume Kit on the Roche MagNA Pure-96 (MP6), and Applied Biosystems QuantStudio7 Flex (QS7) instrument with software version 1.3.
COLLECTION KITS USED WITH THE TEST
This test can be used with the Labcorp At Home COVID-19 Test Home Collection Kit to collect nasal swab specimens at home or in a healthcare setting when ordered by an HCP.
REAGENTS AND MATERIALS
Labcorp At Home COVID-19 Test Home Collection Kit Reagent Manufacturer Catalog # Shipping box Therapak 23586G Return envelope FedEx 163034 Specimen biohazard bag Therapak 16019G Nasal swab Super Brush 59-1187-BULK Saline and tube Sarstedt 51.550.
COVID-19 RT-PCR test Reagent Manufacturer Catalog # DNA and Viral Small Volume Kit (3x purifications)
Roche 06543588001
MagMAX Viral/Pathogen Nucleic Acid Isolation Kit Thermo Fisher A42352 or A MagMAX Viral/Pathogen Extraction Kit (MVP II) Thermo Fisher A TaqPath™ 1-Step Multiplex Master Mix (No ROX) Thermo Fisher A COVID-19_N1-F Primer IDT Custom COVID-19_N1-R Primer IDT Custom
Reagent Manufacturer Catalog # COVID-19_N1-P Probe IDT Custom COVID-19_N2-F Primer IDT Custom COVID-19_N2-R Primer IDT Custom COVID-19_N2-P Probe IDT Custom COVID-19_N3-F Primer IDT Custom COVID-19_N3-R Primer IDT Custom COVID-19_N3-P Probe IDT Custom RP-F Primer IDT Custom RP-R Primer IDT Custom RP-P Probe IDT Custom COVID-19_N_Positive Control IDT Custom Hs_RPP30_Internal Extraction Control IDT Custom
PATIENT INCLUSION/EXCLUSION CRITERIA
Home collection with the Labcorp At Home COVID-19 Test Home Collection Kit is intended for the collection of anterior nasal swabs from individuals age 18 years and older (self-collected), 14 years and older (self-collected under adult supervision), or 2 years and older (collected with adult assistance) when directly ordered by an HCP.
INSPECTION OF SPECIMENS
Applies to specimens received from patients using home collection kit Specimen received from the Labcorp At Home COVID-19 Test Home Collection Kit should be checked for the following criteria before entering the work flow:
- No saline collection tube included
- No swab included within saline collection tube
- No registration code attached to the saline collection tube
- Saline collection tube leaked resulting in no sample for testing
- Kit not registered on Pixel platform (would have to freeze the sample until Pixel customer service contacts customer)
- Accession date is greater than 1 calendar day from the specimen collection date
CONTROLS TO BE USED WITH THE COVID-19 RT-PCR
A negative (no template) control is needed to eliminate the possibility of sample contamination on the assay run and is used on every assay plate. This control is molecular grade, nuclease-free water.
A positive template (COVID-19_N_P) control is needed to verify that the assay run is performing as intended and is used on every assay plate starting at master mix addition at a concentration of 50 copies/μL. The positive template control does not include RNase P target and will result as “undetermined” for that marker.
MULTIPLEX SARS- CoV- N (FAM)
SARS- CoV- N (YY)
RNase P
(Cy5)
Result Interpretation
Report Actions (specimens from clinical sites)
If only one target is positive
+/- SARS-CoV- Indeterminate
INDETERMINATE Sample is repeated once. If results remain the same, it is reported to sender as indeterminate and recommend recollection if patient is still clinically indicated.
NOT DETECTED Report results to sender and appropriate public health authorities.
- Invalid Result INVALID Sample is repeated once. If a second failure occurs, it is reported to sender as invalid and recommend recollection if patient is still clinically indicated.
If Multiplex reagents are not available singleplex testing will be performed and can be interpreted as described below.
COVID-19 RT-PCR test results interpretation SINGLEPLEX SARS- CoV- N (FAM)
SARS- CoV- N (FAM)
SARS- CoV- N (FAM)
RNase P
(FAM)
Result Interpretation
Report Actions (specimens from clinical sites)
DETECTED Report results to sender and appropriate public health authorities. If only one target is positive
+/- +/- SARS-CoV- Indeterminate
INDETERMINATE Sample is repeated once. If results remain the same, it is reported to sender as indeterminate and recommend recollection if patient is still clinically indicated.
NOT DETECTED Report results to sender and appropriate public health authorities.
- Invalid Result INVALID Sample is repeated once. If a second failure occurs, it is reported to sender as invalid and recommend recollection if patient is still clinically indicated.
PERFORMANCE EVALUATION
Some of the validation studies summarized in this EUA Summary to support use of home collection kits with the Labcorp COVID-19 RT-PCR Test were performed with the Pixel COVID-19 Test Home Collection Kit, which is subject of a separate EUA. The Pixel COVID-19 Test Home Collection Kit has the same components and instructions as the Labcorp At Home COVID-19 Test Home Collection Kit, therefore the studies are supportive of both Labcorp home collection kits.
1) Analytical Sensitivity
COVID-19 RT-PCR test (in a singleplex format): Limit of Detection (LoD) for 200 μL sample added to extraction with the Roche MagNA Pure 96 DNA and Viral NA Small Volume Kit
The LoD study established the lowest concentration of SARS-CoV-2 (genome copies(cp)/μL) that can be detected by the COVID-19 RT-PCR test at least 95% of the time. The preliminary LoD was established by testing 10-fold dilutions of SARS-CoV- synthetic RNA. The preliminary LoD was confirmed by testing 20 replicates of 2-fold dilutions (50 cp/μL, 25 cp/μL, 12.5 cp/μL, 6.25 cp/μL, 3.125 cp/μL, and 1.25 cp/μL). The samples of 2-fold dilutions were prepared by spiking the quantified live SARS-CoV- into negative respiratory clinical matrices (NP swabs and BAL). Replicates were extracted using the Roche MagNA Pure 96 DNA and Viral NA Small Volume Kit on the Roche MagNA Pure-96 (MP96) Instrument. The study results showed in the tables below that the LoD of the COVID-19 RT-PCR test (in a singleplex format) is 6.25 cp/μL (19/20 positive).
Positive replicates/total replicates tested at different concentrations of SARS-CoV- 50 cp/μL 25 cp/μL 12.5 cp/μL 6.25 cp/μL 3.125 cp/μL 1.25 cp/μL NP 10/10 10/10 10/10 10/10 3/8 3/ BAL 10/10 10/10 10/10 9/10 2/8 2/ Total 20/20 20/20 20/20 19/20 5/16 5/
Mean Ct at N1 and N2 at different concentrations of SARS-CoV-
50 cp/μl 25 cp/μL 12.5 cp/μL 6.25 cp/μL 3.125 cp/μL 1.25 cp/μL N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N NP 31.08 31.28 31.58 31.66 32.86 33.53 37.30 37.65 36.38 37.49 36.66 37. BAL 29.90 30.63 31.71 32.20 32.27 32.82 35.72 36.19 37.26 38.82 36.81 39.
COVID-19 RT-PCR test (in a multiplex format): Limit of Detection (LoD) for 400μL sample added to extraction with Thermo Fisher MagMAX Viral/Pathogen Nucleic Acid Isolation Kit and 200 μL sample added to extraction with the Roche MagNA Pure 96 DNA and Viral NA Small Volume Kit
To determine the LoD of the multiplex COVID-19 RT-PCR Test, quantified live SARS- CoV-2 virus (from a well characterized positive sample (2e5 genome copies (cp)/uL) was
Positive replicates/total replicates tested at different concentrations of SARS-CoV- 25 cp/μL 12.5 cp/μL 6.25 cp/μL 3.125 cp/μL UTM 10/10 10/10 10/10 10/ Saline 10/10 10/10 10/10 9/ BAL 10/10 10/10 9/10 9/ Mean Ct at N1 and N2 at different concentrations of SARS-CoV- 25 cp/μL 12.5 cp/μL 6.25 cp/μL 3.125 cp/μL N1 N2 N1 N2 N1 N2 N1 N UTM 32.24 32.19 33.58 33.27 34.64 33.70 35.51 34. Saline 33.29 33.95 34.59 35.03 35.44 36.53 36.54 37. BAL 34.09 32.32 34.09 32.32 36.58 36.90 36.87 37.
COVID-19 RT-PCR test (in a multiplex format): Limit of Detection (LoD) for 200μL sample added to extraction with Thermo Fisher MagMAX Viral/Pathogen Nucleic Acid Isolation Kit
To determine the limit of detection, a well characterized positive sample (2x10^5 copies/μL) was diluted into negative sample matrix (BAL and UTM – NP swab) to concentrations of 25, 12.5, 6.25, and 3.125 copies/uL. Each contrived sample was then extracted with the ThermoFisher MagMAX Viral/Pathogen Nucleic Acid Isolation Kit using the Low Volume MagMax procedure. The results produced a limit of detection of 3.125 copies/uL for BAL and UTM.
Positive replicates/total replicates tested at different concentrations of SARS-CoV- Low Volume MagMax 25 cp/uL^ 12.5 cp/uL^ 6.25 cp/uL^ 3.125 cp/uL BAL 10/10 10/10 10/10 10/ UTM 10/10 10/10 10/10 10/ Total 20/20 20/20 20/20 20/
Low Volume MagMax - Mean Ct at N1 and N2 at different concentrations of SARS-CoV- 25 cp/uL 12.5 cp/uL 6.25 cp/uL 3.125 cp/uL N1 N2 N1 N2 N1 N2 N1 N BAL 33.88 32.62 35.24 34.44 35.78 35.23 36.21 35. UTM 33.03^ 32.27^ 33.53^ 33.16^ 35.64^ 36.28^ 36.65^ 37.
COVID-19 RT-PCR test (in a multiplex format): Limit of Detection (LoD) for 200μL sample added to extraction with ThermoFisher MagMAX Viral/Pathogen II (MVP II) Nucleic Acid Isolation Kit using the Hamilton MicroLab STAR and ThermoFisher KingFisher Flex instruments:
To determine the LoD of the multiplex COVID-19 RT-PCR Test, a well characterized positive sample (2x10^5 copies/μL) was diluted into negative clinical matrix from UTM (NP swab), BAL, and saline (anterior nasal swab) and to concentrations of 25, 12.5, 6.25, and 3.125 cp/uL. 6 replicates of each concentration were then extracted with the
ThermoFisher MagMAX Viral/Pathogen II (MVP II) Nucleic Acid Isolation Kit using the Low Volume MagMax procedure (200μL sample added to extraction) on the Hamilton MicroLab STAR and ThermoFisher KingFisher Flex instruments. With either the Hamilton MicroLab STAR and ThermoFisher KingFisher Flex instrument, the ThermoFisher MagMAX Viral/Pathogen II (MVP II) Nucleic Acid Isolation Kit generated the same LoD of 6.25 cp/μL or 31.25 copies/reaction for UTM, BAL and Saline. The results are summarized in the tables below.
Hamilton MicroLab STAR instrument: Positive replicates/total replicates tested at different concentrations of SARS-CoV- 25 cp/μL 12.5 cp/μL 6.25 cp/μL 3.125 cp/μL UTM 6/6 6/6 6/6 5/ BAL 6/6 6/6 6/6 3/ Saline 6/6 6/6 6/6 5/ Total 18/18 18/18 18/18 13/
Hamilton MicroLab STAR instrument: Mean Ct at N1 and N2 at different concentrations of SARS-CoV-
25 cp/μL 12.5 cp/μL 6.25 cp/μL 3.125 cp/μL N1 N2 N1 N2 N1 N2 N1 N UTM 34.69 33.78 35.56 35.09 36.50 36.64 37.87 37. BAL 34.67 33.48 36.60 35.15 37.53 36.39 38.21 39. Saline 35.23 33.85 35.65 34.59 37.54 37.25 38.41 38.
ThermoFisher KingFisher Flex instrument: Positive replicates/total replicates tested at different concentrations of SARS-CoV- 25 cp/μL 12.5 cp/μL 6.25 cp/μL 3.125 cp/μL UTM 6/6 6/6 6/6 6/ BAL 6/6 6/6 6/6 4/ Saline 6/6 6/6 6/6 3/ Total 18/18 18/18 18/18 13/
ThermoFisher KingFisher Flex instrument: Mean Ct at N1 and N2 at different concentrations of SARS-CoV-
25 cp/μL 12.5 cp/μL 6.25 cp/μL 3.125 cp/μL N1 N2 N1 N2 N1 N2 N1 N UTM 33.23 32.32 33.89 33.05 35.69 35.23 36.69 37. BAL 34.54 33.33 35.60 34.00 36.22 35.26 38.47 38. Saline 33.95 32.52 35.83 34.65 36.87 36.21 38.64 39.
2) Analytical Sensitivity
This test is using the primers and probes published by CDC and used in the CDC COVID-19 Diagnostic Panel without sequence modifications. This test has Right of Reference to the 2019-nCoV Real-Time RT-PCR Diagnostic Panel (CDC) and the
BLAST analysis showed no homology with primers and probes of the COVID-19 RT- PCR test for the organisms listed in the table below.
In silico analysis:
Human parainfluenza virus 3 Not detected^ Not detected^ Not detected^
ATCC VR-1782; ATCC-
Human parainfluenza virus 4b Not detected Not detected Not detected
ATCC VR-1377;
CH 19503*
Human respiratory syncytial virus Not detected Not detected Not detected ATCC VR-1580; 18537*
Human rhinovirus 61 Not detected Not detected Not detected
ATCC VR-1171;
6669-CV39*
Influenza A Not detected Not detected Not detected
ATCC VR-1679D; H3N2,
A/Hong Kong/8/ (2e^6)
Influenza B Not detected Not detected Not detected
ATCC VR-1735D;
B/Taiwan/2/ (3e^6)
Legionella pneumophila Not detected Not detected Not detected
ATCC 33152D-5;
Philadelphia- (1.5e^6)
Middle East Respiratory Syndrome coronavirus Not detected^ Not detected^ Not detected
ATCC VR-3248SD;
MERS
(6e^5) Mycobacterium tuberculosis Not detected Not detected Not detected ATCC 25177; H37Ra*
Mycoplasma pneumoniae Not detected^ Not detected^ Not detected
ATCC 15531D; FH of Eaton Agent (3e^6) Severe Acute Respiratory Syndrome coronavirus
Not detected Not detected 30.768 BEI NR-3882; SARS*
Streptococcus pneumoniae Not detected Not detected Not detected ATCC 33400D- (3e^6)
Streptococcus pyogenes Not detected Not detected Not detected
ATCC 12344D-5; T
(3e^6)
Pathogen Strain GenBank Acc#
% Homology Test Forward Primer
% Homology Test Reverse Primer
% Homology Test Probe Candida albicans All All 0 0 0 Neisseria meningitidis All^ All^0
4) Clinical Evaluation
A contrived clinical study was performed to evaluate the performance of the COVID- 19 RT-PCR test. A total of 100 individual clinical respiratory samples, 50 NP swabs and 50 BALs, were used in this study. 100 negatives and 80 contrived positives were tested. Negative samples include 50 NP swabs and 50 BALs. Positive samples were comprised of 40 NP swabs and 40 BALs spiked with quantitated live SARS-CoV-2. 10 samples each were spiked at 8x, 4x, 2x, and 1X LoD. In one contrived BAL sample, prepared at LoD, N3 target was not determined. The positive and negative percent agreements between the COVID-19 RT-PCR test and the expected results in NP swabs and BALs are shown below:
Clinical performance of the COVID-19 RT-PCR test with NP swabs:
COVID-
19 RT-
PCR test
SARS-CoV- 2 concentration
Number of NP swabs
N1 target % Positive (95% CIs)
N2 target % Positive (95% CIs)
N3 target % Positive (95% CIs) 1x LoD 10 100% (72.25 – 100)
2x LoD 10 100% (72.25 – 100)
4x LoD 10 100% (72.25 – 100)
8x LoD 10 100% (72.25 – 100)
Negative 50 0 (NA)
(NA)
(NA)
NA = Not available
Performance of the COVID-19 RT-PCR test against the expected results are: Positive Percent Agreement 40/40 = 100% (95% CI: 91.24% - 100%) Negative Percent Agreement 50/50 = 100% (95% CI: 92.87% - 100%)
Pseudomonas aeruginosa All^ All^0 0 Staphylococcus aureus All All 0 0 0
A clinical evaluation of the Labcorp COVID-19 RT-PCR test was performed with 635 positive upper respiratory specimens with results shown in the table below. Comparator results for the clinical specimens was obtained with a highly sensitive FDA EUA RT- PCR test.
FDA EUA RT-PCR Test Positive Indeterminate Negative Total
Labcorp COVID- RT-PCR test
Positive 612 0 0 612 Indeterminate 11 0 0 11 Negative 12 0 0 12 Total 635 0 0
Positive Percent Agreement = 612/624= 98.08% (95% CI: 96.67% - 98.90%) Indeterminate Rate = 11/635 = 1.7% Number of low positive specimens = 23/624 = 3.69% Note: There was insufficient material remaining to re-test the samples with indeterminate results. Indeterminate sample are excluded from the PPA calculation
A clinical evaluation of the Labcorp COVID-19 RT-PCR test was performed with 30 positive and 30 negative upper respiratory specimens with results shown in the table below. Comparator results for the clinical specimens was obtained with a highly sensitive FDA EUA RT-PCR test.
FDA EUA RT-PCR Test Positive Negative Total Labcorp COVID- RT-PCR test
Positive 30 0 0 Negative 0 30 30 Total 30 30
Positive Percent Agreement = 30/30 = 100% (95% CI: 88.65% - 100%) Negative Percent Agreement = 30/30 = 100% (95% CI: 88.65% - 100%) Number of low positive samples = 8/30 = 26.7%
5) Comparison Between Singleplex and Multiplex COVID-19 RT-PCR Test
A total of 93 clinical nasopharyngeal (NP) samples were evaluated in this comparison study. Each patient sample was tested by the COVID-19 RT-PCR test using both singleplex and multiplex formats and the results of the two were compared. This comparison showed 100% concordance between singleplex and multiplex test results for a clinical sample. Of the 93 clinical samples, 16 generated positive results and 77 generated negative results by the COVID-19 RT-PCR test using both singleplex and multiplex formats.
6) Validation of the ThermoFisher MagMAX Viral/Pathogen Nucleic Acid Isolation Kit using the Low Volume MagMax procedure (200μL Extraction Volume)
Refer to “Analytical Sensitivity” for the LoD study performed with the ThermoFisher MagMAX Viral/Pathogen Nucleic Acid Isolation Kit using the Low Volume MagMax procedure (200 μL extraction volume).
Clinical performance of the 200μL versus the 400μL extraction procedure was demonstrated with a set of clinical samples extracted with both methods. One extraction plate for each of the extraction methods was run for clinical concordance. A total of 93 samples were on the plate, including 36 positives, 7 of which were low positive. The results of the clinical comparison were 100% concordant. 36/ positives were detected as positive and 57/57 negatives were not detected. An observed Ct shift of 1 Ct is observed with the reduced extraction volume but did not affect clinical sample results, even at samples near the limit of detection.
7) Usability Study - Self-Collection Validation (Labcorp At Home COVID-19 Test Home Collection Kit OR Pixel by LabCorp COVID-19 Test Home Collection Kit
Adults age 18 years or older: 30 participants were enrolled in a self-collection study. After signing a consent form, the participants were presented with 2 saline tubes, 2 cotton swabs and the instructions provided in the Pixel COVID-19 Test Home Collection Kit. Six (6) participants were given an additional tube for a total of 3 tubes to test the effect of shipping samples without a gel pack. Participants were not observed during the study. After sample collection, 1 of the 2 (or 2 of the 3) collection tubes were spiked with a known COVID-19 positive sample in the laboratory after clinical matrix was collected from participants. These samples were then packaged up as described above and shipped back to the lab via FedEx (transit time, 72hr) where they were unpacked and tested using the FDA Authorized Labcorp COVID-19 RT-PCR Test, non-multiplexed version.
This study evaluated the users’ ability to properly collect a swab, and shipping stability while the sample is in possession of FedEx (not while in the drop box). This study also evaluated if swab material (cotton) could cause any false positive or false negative reactions or if it could impact the assay’s internal controls.
The results of the self-collection validation were consistent with expected results. All positives (36/36) remained positive 72 hours post shipping. No false positives were detected (30/30). All samples had strong Human RnaseP signals indicating all participants were successful in collecting human biological material. Samples shipped without a gel pack (a worst-case shipping condition) showed no change in the qualitative result for either RNaseP or COVID-19 targets.
Children ages 2 years-17 years: 30 subjects were enrolled in a home-collection study, children 13 years and younger (n=14) had an adult parent or guardian collect the sample and children 14 years and older (n=16) self-collected their sample. Study
samples (10x LoD of the Labcorp COVID-19 RT-PCR Test) were created by diluting a well characterized positive sample in saline. These samples as well as 10 negative samples were tested for stability at 0hr and after a temperature excursion of 40C for 108hrs (4 days plus 12 hours).
At time point 0hr and 108hr, 20 of the 20 (100%) contrived low positive samples tested positive for SARS-CoV-2 with the Labcorp COVID-19 RT-PCR Test. At time point 0hr, 9 of the 10 (90%) contrived high positive samples tested positive for SARS-CoV-2 with the Labcorp COVID-19 RT-PCR Test. At time point 108hr, 10 of the 10 (100%) contrived high positive samples tested positive for SARS-CoV-2 with the Labcorp COVID-19 RT-PCR Test. At time point 0hr and 108hr, all 10 negative samples tested negative for SARS-CoV-2 with the Labcorp COVID-19 RT-PCR Test. The average Ct difference post-temperature excursion at 40C demonstrated that the Ct of samples at 0hr (baseline) did not differ by more than 3 Ct to samples exposed to 40C for 108 hours.
Sample stability studies were conducted using the winter profile in the table below to confirm that samples shipped using a FedEx drop box will not generate false results and there will be minimal to no loss of signal for positive specimens.
Temperature Cycle Period Cycle Period Hours Total Time Hours
- 10C 1 8 8 18C 2 4 12 - 10C 3 2 14 10C 4 36 50 - 10C 5 6 56
30 contrived low positive samples (2x LoD of the Labcorp COVID-19 RT-PCR Test) and 10 contrived high positive samples (10x LoD of the Labcorp COVID-19 RT-PCR Test) were created by diluting a well characterized positive sample in saline. These samples as well as 10 negative samples were tested for the duration of the winter profile testing.
At time point 0hr, 30 of the 30 contrived low positive samples tested positive for SARS-CoV-2 with the Labcorp COVID-19 RT-PCR Test. At time point 56 hr, 29 of the 30 (96.67%) contrived low positive samples tested positive for SARS-CoV-2 with the Labcorp COVID-19 RT-PCR Test. At time point 0hr and 56hr, 10 of the 10 (100%) contrived high positive samples tested positive for SARS-CoV-2 with the Labcorp COVID-19 RT-PCR Test. At time point 0hr and 56 hr, all 10 negative samples tested negative for SARS-CoV-2 with the Labcorp COVID-19 RT-PCR Test.
In summary, the shipping stability study data supports a sample shipping stability claim up to 4 days in summer conditions and up to 56 hours in winter conditions. An extended winter shipping stability study will be conducted to further support a claim up to 4 days in winter conditions..
9) Validation of New Foam Swabs for Shipping Stability
A total of 40 samples, were collected by participants who swabbed their anterior nasal cavity according to the Pixel kit instructions, 20 participants were given the Azer Foam swab and 20 participants were given a Purtian Foam swab (swab type used in Quantigen study). 20 positive samples (10 for each swab manufacturer) were then contrived by pipetting positive sample matrix (30 μL) into the tube followed by vortexing. The positive sample matrix was created by the dilution of a well characterized positive sample (2e5 cp/μL) to 1e3 cp/μL. Because the tubes contained approximately 3 mL of saline, this results in a final concentration of approximately 50 copies/reaction which is <2x the 31.25 copies/reaction LOD of the Labcorp COVID- 19 test.
Temperature Excursion Conditions
The 20/20 negatives remained negative throughout the time-course for both swabs with Ct values for the RP internal control <40 indicating good sample collection. The 20/20 positives were positive at time 0, after the temperature excursion, and after sitting at 4 ℃ for an additional 94 hrs (total of 144 hrs). The average Ct values for N1, N2 and RP did not deviate substantially throughout the stability experiment.
Average Ct during stability. Error Bars are standard deviation.
Temperature Cycle Period Cycle Period Hours Total Time Hours 40°C 1 6 6 22°C 2 16 22 40°C 3 2 24 35°C 4 22 46 40°C 5 4 50
0
5
10
15
20
25
30
35
40
N1 N2 RP
Average Ct
0hr TEX 144hr
