Summary of key demographic and epidemiological data as well as results from each of the included studies, arranged by sample size from highest
| Author | Publication (submission) dates | Design/enrolment | Setting | Exclusions | n | COVID-19 prevalence (%) | Admission rate (%) | LUS protocol | LUS Dx threshold | Reference standard | Sensitivity LUS (%) (95% CI) | Specificity LUS (%) (95% CI) | TP | FN | FP | TN | Prior training and experience |
| Volpicelli et al | December 2020 (March 2021) | Prospective, convenience | ED (74%) COVID unit (16%) ICU (10%) | None | 1462 | 70 | 34 | ‘Complete’ (>12 zones) | High or intermediate pattern | PCR | 90 (88 to 92) | 53 (48 to 57) | 921 | 101 | 209 | 231 | Documented evidence in performing LUS |
| Colombi et al | July 2020 (October 2020) | Retrospective, convenience | ED | Those without clinical or epidemiological suspicion | 486 | 70 | 100 | 12 zones | >1 zone | PCR | 91 (84 to 94) | 66 (58 to 74) | 311 | 29 | 49 | 97 | No details provided |
| Sorlini et al | June 2020 (October 2020) | Retrospective, convenience | ED | None | 384 | – | 100 | 12 zones | >2 zones positive | PCR | 92 (88 to 95) | 65 (55 to 74) | 264 | 23 | 34 | 63 | LUS accreditation, 1-day LUS course and >150 supervised scans |
| Bianchi et al | October 2020 (April 2021) | Prospective, convenience | ED | Pregnancy, confirmed COVID-19 infection on PCR | 360 | 39 | 100 | 12 zones | Summary assessment | PCR | 86 (79 to 91) | 71 (66 to 77) | 120 | 20 | 64 | 156 | LUS accreditation and >50 LUS examinations |
| Pivetta et al | July 2020 (October 2020) | Prospective, convenience | ED | Intubated patients Confirmed cases Those requiring acute mental health care | 228 | 47 | 40 | 12 zones | Operator interpretation | PCR | 94 (88 to 97) | 95 (90 to 98) | 101 | 6 | 6 | 115 | LUS accreditation, single learning module and >40 supervised scans |
| Lieveld et al | July 2020 (October 2020) | Prospective, convenience | ED | Patients with uninterpretable LUS images | 187 | 46 | 100 | 12 zones | >2 zones positive | PCR/final Dx | 92 (84 to 96) 92 (84 to 96) | 71 (61 to 79) 80 (70 to 87) | 79 | 7 | 29 | 71 | Certified and >20 supervised scans |
| Brenner et al | December 2020 (March 2021) | Retrospective, convenience | ED Medical ward | None | 174 | 53 | 77 | 12 zones | Summary assessment | PCR | 86 (77 to 92) | 72 (61 to 81) | 79 | 13 | 23 | 59 | Credentialled in LUS |
| Schmid et al | July 2020 (December 2020) | Retrospective, convenience | ED | None | 135 | 29 | 73 | 12 zones | >2 zones positive | PCR/CT | 77 (62 to 87) 65 (43 to 82) | 77 (68 to 84) 73 (43 to 90) | 30/13 | 9/7 | 22/3 | 74/8 | Training in POCUS |
| Zanforlin et al | June 2020 (December 2020) | Retrospective, convenience | ED | None | 111 | 41 | 48 | 20 zones | LUS score >3 | Final Dx | 85 (72 to 92) | 75 (64 to 40) | 39 | 7 | 16 | 49 | No details provided |
| Gibbons et al | November 2020 (February 2021) | Prospective, convenience | ED | Pregnancy | 110 | 75 | 100 | 8 zones | >2 zones positive | CT | 98 (91 to 99) | 35 (20 to 53) | 79 | 2 | 19 | 10 | ACEP credentialled and >25 LUS scans |
| Tung-Chen et al | October 2020 (January 2021) | Prospective, convenience | ED | None | 96 | 61 | 77 | 12 zones | >2 zones positive | PCR | 72 (59 to 82) (irregular pleural line) 87 (confluent b-lines) | 66 (49 to 79) (irregular pleural line) 33 (confluent b-lines) | 39 | 15 | 12 | 23 | Experienced sinologists, performing >10 US scans per week |
| Haak et al | May 2020 (November 2020) | Prospective, convenience | ED | Age <16 CCF No LUS Confirmed COVID | 93 | 29 | – | 12 zones | >1 zone | PCR/CT | 96 (80 to 99) 60 (23 to 88) | 59 (48 to 70) 62 (41 to 79) | 23/3 | 1/2 | 28/8 | 41/13 | >2.5 years of POCUS experience |
| Narinx et al | June 2020 (September 2020) | Retrospective, convenience | ED | None | 90 | 17 | – | 12 zones | >1 zone | PCR | 93 (70 to 99) | 21 (14 to 32) | 14 | 1 | 59 | 16 | Board certified for LUS and >5 years of experience in US |
| Karagoz et al | May 2020 (December 2020) | Prospective, convenience | ED | Age <18 Chest pain Pregnant Hypotensive Previous thoracic surgery If unable to obtain optimal images | 72 | 48 | 100 | 12 zones | Not defined | CT | 97 (85 to 99) | 92 (80 to 97) | 32 | 1 | 3 | 36 | 5 years of experience, 3-hour theory module, 20 live demonstrations |
| Jalil et al | September 2020 (October 2020) | Retrospective, convenience | Mixed secondary care setting (LUS performed <24 hours from presentation) | None | 69 | 52 | 100 | 8 zones | LUS-COV criteria (summary assessment of images) | PCR | 86 (71 to 94) | 91 (76 to 97) | 31 | 5 | 3 | 30 | No details provided, but all 3 operators were intensive care physicians |
| Fonsi et al | May 2020 (September 2020) | Prospective, convenience | ED/COVID unit | None | 63 | 70 | 100 | 12 zones | Not defined | PCR | 68 (53 to 80) | 79 (57 to 91) | 30 | 14 | 4 | 15 | No details provided |
| Bosso et al | May 2020 (October 2020) | Prospective, convenience | ED/COVID unit | None | 53 | 49 | 100 | 12 zones | Severity score used | PCR | 73 (54 to 86) (optimal cut-off >12.5) | 89 (72 to 96) (optimal cut-off >12.5) | 19 | 7 | 3 | 24 | No details provided |
| Spiedel et al | September 2020 (December 2020) | Prospective, convenience | Admission ward (LUS performed <24 hours from presentation) | If PCR result already available ICU admissions | 49 | 22 | 100 | 12 zones | Severity score used | Final Dx | 91 (62 to 98) (optimal cut-off score >8) | 76 (61 to 87) (optimal cut-off score >8) | 10 | 1 | 9 | 29 | Specific POCUS qualification, >3 years of experience in US, >1 year of experience in LUS |
| Walsh et al | July 2020 (September 2020) | Retrospective, convenience | ED | History of Congesitve cardiac failure or other pathology likely to affect LUS | 49 | 12 | 39 | Continuous posterior assessment+single anterior and axillary zones | Operator interpretation | CT | 100 (76 to 100) | 80 (49 to 94) | 12 | 0 | 2 | 8 | Facile in LUS, but no specific details provided |
| Pare et al | April 2020 (June 2020) | Retrospective, convenience | ED | If there was no CXR, LUS or PCR test If the patient had an underlying condition predisposing them to B-lines on LUS | 43 | 70 | 72 | Unclear (median number of saved images=6) | >1 B-line | PCR | 89 (72 to 96) | 56 (33 to 77) | 24 | 3 | 7 | 9 | No details provided. Images overinterpreted by 3 fellowship trained physicians |
Dx, diagnosis; FN, false negative; FP, false positive; ICU, intensive care unit; LUS, lung ultrasound; POCUS, point-of-care ultrasound; TN, true negative; TP, true positive.