Development and evaluation of a flocked nasal midturbinate swab for self-collection in respiratory virus infection diagnostic testing.
Author(s): Smieja M, Castriciano S, Carruthers S, So G, Chong S, Luinstra K, Mahony JB, Petrich A, Chernesky M, Savarese M, Triva D
Publication: J Clin Microbiol, 2010, Vol. 48, Page 3340-2
PubMed ID: 20610685 PubMed Review Paper? No
Purpose of Paper
This paper compared adequacy of sequential self-collected nasal specimens collected with flocked midturbinate swabs to healthcare worker-collected nasal and nasopharyngeal swab specimens collected using two different swab types (flocked midturbinate swab and rayon pernasal swab) for collecting respiratory epithelial cells from asymptomatic volunteers and investigated the correlations between epithelial cell numbers and beta-actin gene copy numbers in a subset of these specimens. Concordance among sequentially self-collected nasal flocked swab specimens from symptomatic volunteers for the detection of respiratory viruses using a multiplex PCR assay was also investigated.
Conclusion of Paper
An adequate specimen was obtained in 87.3% of the first self-collected nasal swabs and in 98.2% of the second self-collected swabs. The sequentially collected swabs were equivalent for diagnosing respiratory virus infections by multiplex PCR with concordant virus infections detected in 82.9% (29/35) of participants although cell yields were higher from the second self-collected nasal swabs than the first self-collected specimens. Among asymptomatic volunteers, the first self-collected nasal swab had lower numbers of epithelial cells than the second self-collected nasal swab. Both the first and second self-collected nasal swab yielded comparable or higher numbers of epithelial to the healthcare worker-collected rayon nasal and nasopharyngeal swabs. While the first self-collected nasal swab obtained fewer epithelial cells than the healthcare worker-collected flocked nasal and nasopharyngeal swabs, the second self-collected nasal swab yielded more or comparable numbers of epithelial cells. Epithelial cell counts were very strongly correlated with beta-actin copy numbers and beta-actin levels were similar in self- and healthcare worker-collected flocked nasal and nasopharyngeal swabs but lower in rayon nasal and nasopharyngeal swab specimens.
Studies
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Study Purpose
This study compared adequacy of sequential self-collected nasal specimens collected with flocked midturbinate swabs to healthcare worker-collected nasal and nasopharyngeal swab specimens collected using two different swab types (flocked midturbinate swab and rayon pernasal swab) for collecting respiratory epithelial cells from asymptomatic volunteers. Correlations between epithelial cell numbers and beta-actin gene copy numbers in a subset of these specimens were also investigated. Healthy adult volunteers (n=55) were asked to self-collect a nasal specimen by inserting a flocked nasal swab up to 5.5 cm into the nasal cavity following printed instructions with illustrations (details not provided) and repeating the procedure in the same nostril for a second specimen. Healthcare workers then collected the two additional nasal swabs in the opposite nostril in random order with a flocked midturbinate nasal swab and a rayon pernasal swab. Swabs were placed in universal transport media, vortexed, and then centrifuged. The pellet was resuspended in buffered saline and 25 µl of suspension was added to glass slide wells, air dried, fixed, stained for DFA testing, and respiratory epithelial cells were counted and averaged over four high-powered fields (HPF) at 400X. Nasopharyngeal specimens were obtained from a subset of volunteers (20/55) by healthcare workers following the nasal swab collection in the same nostril collected in random order with a flocked midturbinate nasal swab and a rayon pernasal swab. Beta-actin gene DNA copies were quantified by PCR in the self-collected nasal swab specimens and healthcare worker-collected nasal and nasopharyngeal swab specimens from the subset of participants. Details of PCR methodology were not provided. Participants were asked to assess the ease of self-collection, discomfort level, and swab preferences.
Summary of Findings:
An adequate specimen, defined as >25 cells/HPF, was obtained in 87.3% (48/55) of the first self-collected swabs and in 98.2% (54/55) of the second self-collected swabs. Cell yields varied significantly between the first and second self-collected nasal swab specimens, between the healthcare worker-collected flocked and rayon nasal swab specimens, and between the flocked and rayon swab nasopharyngeal specimens (P<0.001, all). The first self-collected nasal swab obtained more epithelial cells than the healthcare worker-collected rayon nasal swab (P=0.001), comparable yields to the healthcare worker-collected rayon nasopharyngeal swabs (P=0.96). While the first self-collected nasal swab yielded fewer epithelial cells than the healthcare worker-collected flocked nasal and nasopharyngeal swabs (P<0.001 and P=0.003; respectively), the second self-collected nasal swab yielded comparable numbers to the healthcare worker-collected flocked nasal and nasopharyngeal swabs (P=0.80 and P=0.89, respectively) and superior numbers to rayon nasopharyngeal and nasal swabs (P<0.001, both). Epithelial cell counts were very strongly correlated with beta-actin copy numbers (R=0.9; P<0.001) and beta-actin levels were similar in self- and healthcare worker-collected flocked nasal and nasopharyngeal swabs but lower in rayon nasal and nasopharyngeal swab specimens (P<0.001, both). Eighty-seven percent of volunteers reported little or no difficulty in self-swabbing with 65% reporting no or mild discomfort, 31% reporting moderate discomfort, and 4% reported severe discomfort. Only 24% of volunteers preferred healthcare worker collection, 40% preferred self-swabbing, and 36% expressed no preference.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Normal
Platform:
Analyte Technology Platform DNA PCR Cell count/volume Light microscopy Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Acquisition Method of cell acquisition Self-collected nasal swab
Healthcare worker-collected nasal swab
Healthcare worker-collected nasopharyngeal swab specimen
Flocked midturbinate nasal swab
Rayon pernasal swab
PCR Specific Targeted nucleic acid beta-actin
Biospecimen Aliquots and Components Aliquot sequential collection 1st collection
2nd collection
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Study Purpose
This study compared sequentially self-collected nasal flocked swab specimens for the detection of respiratory viruses using a multiplex PCR assay. Symptomatic volunteers (n=108) self-swabbed within 3 days of acute respiratory infection symptom onset by inserting a flocked nasal swab up to 5.5 cm into the nasal cavity following printed instructions with illustrations (details not provided) and repeating the procedure in the same nostril for a second specimen. Swabs were placed in universal transport media and returned to the hospital within 5 days. DNA was extracted using NucliSens easyMAG and analyzed by multiplex PCR with the xTAG respiratory virus panel for 16 virus types and subtypes (influenza A seasonal H1, seasonal H3, and H1N1 A/swine/California/04/2009; influenza B; respiratory syncytial virus; parainfluenza 1, 2, 3, and 4; metapneumovirus; rhino/enterovirus; bocavirus; coronavirus 229E, OC43, and HKU1; and adenovirus).
Summary of Findings:
A total of 38.9% (42/108) symptomatic volunteers had viruses detected in their nasal swabs, 35 of which submitted two swabs. The first and second self-collected swabs were equivalent for diagnosing respiratory virus infections by multiplex PCR with concordant virus infections detected for 82.9% (29/35) of participants. Among the six discrepant swab results, three were positive with the first swab (one rhino/enterovirus, one respiratory syncytial virus subgroup A, and one H1N1 virus) while 3 were positive with the second swab (all rhino/enteroviruses).
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Pneumonia/Respiratory Infection
Platform:
Analyte Technology Platform DNA PCR Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) PCR Specific Targeted nucleic acid influenza A seasonal H1
influenza A seasonal H3
influenza A H1N1 A/swine/California/04/2009
influenza B
respiratory syncytial virus
parainfluenza 1
parainfluenza 2
parainfluenza 3
parainfluenza 4
metapneumovirus
rhino/enterovirus
bocavirus
coronavirus 229E
coronavirus OC43
coronavirus HKU1
adenovirus
Biospecimen Aliquots and Components Aliquot sequential collection 1st collection
2nd collection