Rapid Olfactory Test Shows Potential as Screening Tool for COVID-19
By LabMedica International staff writers Posted on 20 Jul 2021 |
Illustration
A study that evaluated the feasibility of a novel, objective olfactory test as part of an initial screening for COVID-19 in adults with unknown disease status has concluded that olfactory dysfunction (OD) is one of the earliest and strongest predictors of COVID-19 infection, and thus is promising as a disease screening tool.
In the prospective, cross-sectional study, researchers at University of California, San Diego (La Jolla, CA, USA) enrolled healthy adults (aged ≥ 18 years) from a single college campus COVID-19 screening site. Participants were screened for OD using a novel scent card (SAFER Diagnostics) followed immediately by polymerase chain reaction (PCR) testing for SARS-CoV-2 from nasopharyngeal swabs. The SAFER card contained a single scent in a scratch-and-sniff label that the participant identified from 8 answer options: lemon, grape, floral, blueberry, banana, mint, unsure, or no scent. Answers were processed electronically via a QR code. An incorrect choice was classified as OD. Participant demographics, medical history, COVID-19 symptoms, and subjective smell function on a binary and 10-point visual analog scale (VAS, with 0 indicating no sense of smell and 10 indicating normal sense of smell) were also collected.
A total of 163 participants were prospectively screened for OD using the scent card followed by SARS-CoV-2 PCR testing. Of those who tested PCR-positive for COVID-19, 75% (12 out of 16) failed olfactory screening compared with 4.8% (7 out of 147) among those testing PCR-negative for COVID-19. The sensitivity, specificity, positive predictive value, and negative predictive value of the scent card in detecting those with COVID-19 were 75.0%, 95.2%, 63.2%, and 97.2%, respectively. Including the symptom fatigue along with OD achieved 93.8% sensitivity and 89.8% specificity in disease screening. The addition of fever and cough did not further increase sensitivity.
While only 37.5% (6 out of 16) of COVID-19 test-positive participants reported subjective anosmia, 75% failed screening with the scent card. A failed scent card screen was the greatest predictor of COVID-19 positivity (odds ratio [OR], 80.24; 95% CI, 14.77-435.90) when compared with other symptoms including cough, fever, fatigue, and a history of COVID-19 exposure. Thus, the study demonstrated that a rapid psychophysical olfaction test is feasible as a screening tool for COVID-19.
Related Links:
University of California, San Diego
In the prospective, cross-sectional study, researchers at University of California, San Diego (La Jolla, CA, USA) enrolled healthy adults (aged ≥ 18 years) from a single college campus COVID-19 screening site. Participants were screened for OD using a novel scent card (SAFER Diagnostics) followed immediately by polymerase chain reaction (PCR) testing for SARS-CoV-2 from nasopharyngeal swabs. The SAFER card contained a single scent in a scratch-and-sniff label that the participant identified from 8 answer options: lemon, grape, floral, blueberry, banana, mint, unsure, or no scent. Answers were processed electronically via a QR code. An incorrect choice was classified as OD. Participant demographics, medical history, COVID-19 symptoms, and subjective smell function on a binary and 10-point visual analog scale (VAS, with 0 indicating no sense of smell and 10 indicating normal sense of smell) were also collected.
A total of 163 participants were prospectively screened for OD using the scent card followed by SARS-CoV-2 PCR testing. Of those who tested PCR-positive for COVID-19, 75% (12 out of 16) failed olfactory screening compared with 4.8% (7 out of 147) among those testing PCR-negative for COVID-19. The sensitivity, specificity, positive predictive value, and negative predictive value of the scent card in detecting those with COVID-19 were 75.0%, 95.2%, 63.2%, and 97.2%, respectively. Including the symptom fatigue along with OD achieved 93.8% sensitivity and 89.8% specificity in disease screening. The addition of fever and cough did not further increase sensitivity.
While only 37.5% (6 out of 16) of COVID-19 test-positive participants reported subjective anosmia, 75% failed screening with the scent card. A failed scent card screen was the greatest predictor of COVID-19 positivity (odds ratio [OR], 80.24; 95% CI, 14.77-435.90) when compared with other symptoms including cough, fever, fatigue, and a history of COVID-19 exposure. Thus, the study demonstrated that a rapid psychophysical olfaction test is feasible as a screening tool for COVID-19.
Related Links:
University of California, San Diego
Latest COVID-19 News
- New Immunosensor Paves Way to Rapid POC Testing for COVID-19 and Emerging Infectious Diseases
- Long COVID Etiologies Found in Acute Infection Blood Samples
- Novel Device Detects COVID-19 Antibodies in Five Minutes
- CRISPR-Powered COVID-19 Test Detects SARS-CoV-2 in 30 Minutes Using Gene Scissors
- Gut Microbiome Dysbiosis Linked to COVID-19
- Novel SARS CoV-2 Rapid Antigen Test Validated for Diagnostic Accuracy
- New COVID + Flu + R.S.V. Test to Help Prepare for `Tripledemic`
- AI Takes Guesswork Out Of Lateral Flow Testing
- Fastest Ever SARS-CoV-2 Antigen Test Designed for Non-Invasive COVID-19 Testing in Any Setting
- Rapid Antigen Tests Detect Omicron, Delta SARS-CoV-2 Variants
- Health Care Professionals Showed Increased Interest in POC Technologies During Pandemic, Finds Study
- Set Up Reserve Lab Capacity Now for Faster Response to Next Pandemic, Say Researchers
- Blood Test Performed During Initial Infection Predicts Long COVID Risk
- Low-Cost COVID-19 Testing Platform Combines Sensitivity of PCR and Speed of Antigen Tests
- Finger-Prick Blood Test Identifies Immunity to COVID-19
- Quick Test Kit Determines Immunity Against COVID-19 and Its Variants