Overview of Study Quality*
| Study, Year | Patient Selection | Index Test | Reference Std | Flow & Timing | Overall |
|---|---|---|---|---|---|
| Biggs, 2013 | L | L | L | L | L |
| Grotto, 2003 | L | L | L | L | L |
| Llor, 2012 | L | L | L | L | L |
| Lennon, 2010 | L | L | L | L | L |
| Rea, 2001 | L | L | L | L | L |
| Brigden, 1999 | L | L | L | L | L |
| Krabbe, 1981 | L | L | L | L | L |
| Aronson, 1982 | L | L | L | L | L |
| Gartzonika, 2012 | L | L | L | L | L |
| Hossain, 1989 | L | H | L | L | M |
| Sumaya, 1985 | H | L | L | L | M |
| Ventura, 2004 | L | H | L | L | M |
| Ginsburg, 1977 | U | H | L | L | M |
| Fleisher, 1983 | L | L | L | H | M |
| Chretien, 1977 | L | H | H | L | H |
| Ho-Yen, 1981 | L | H | H | H | H |
| Balfour, 2005 | L | H | H | L | H |
↵* L = 0, M = 1, and H = 2+ with high likelihood of bias.