Table 2.
Performance characteristics based on established cutoff values for rectal evacuation disorder, fast or slow colonic transit, bile acid diarrhea, and carbohydrate maldigestion (reproduced from ref.11) and average costs of different biomarkers in selected cities in the United States (New York, NY, Los Angeles, CA, Chicago, IL, Miami, FL, Dallas, TX, Omaha, NE, St Louis, MS and Birmingham, AL) obtained from a publicly available website (https://www.fairhealthconsumer.org/) and including facility fees. Estimates are based on the 80th percentile and correspond to in-network costs.
| Biomarker | Cut-offs | Sn | Sp | PPV | NPV | +LR | −LR | Ref. # | CPT | Median charge US $ |
|---|---|---|---|---|---|---|---|---|---|---|
| Rectal Evacuation disorders | ||||||||||
| Digital rectal exam (DRE) | >2 findings on DRE | 83.9 | 68.1 | 49 | 92.8 | 2.6 | 0.2 | 16 | ||
| Anorectal manometry: rectoanal pressure gradient | < −40 mm Hg | 32.4 | 100 | 100 | 85.5 | >10 | 0.7 | 17 | 91122 | 1194.5 |
| Balloon expulsion test | 22 seconds | 77.8 | 69.8 | 39.2 | 92.6 | 2.6 | 0.3 | 18 | ||
| Rectal gas volume | >20 mL | 38.1 | 89.1 | 46.6 | 85.2 | 3.5 | 0.7 | 19 | ||
| Rectal area on Scout film | >900 mm2 | 39.5 | 73.8 | 27.4 | 83.0 | 1.5 | 0.8 | 19 | 74018 | 294.5 |
| Slow Transit Constipation | ||||||||||
| Stool burden score on abdo. x-ray | >7 | 86.9 | 54.5 | 27.1 | 95.5 | 1.9 | 0.2 | 20 | 74018 | 294.5 |
| Colonic transit with scintigraphy: geometric center, GC | GC 48h <2.1 | 82 | 65 | 31.3 | 94.9 | 2.4 | 0.3 | 21 | 78266 | 2256.5 |
| Fast transit diarrhea | ||||||||||
| Colonic transit with scintigraphy | GC 24h >3.8 | 31.6 | 87.2 | 21.5 | 91.9 | 2.5 | 0.8 | 22 | 78266 | 2256.5 |
| Bile Acid diarrhea | ||||||||||
| 75 SeHCAT retention | 3-day 34% | 100 | 94 | 33 | 77 | 1.7 | 0.9 | 23 | ||
| 48-hour fecal bile acid | 1° BA >4% + total BA >1000μmol | 46 | 97 | 83.6 | 84.3 | 15.3 | 5.1 | 24 | 82239 | 102 |
| FGF-19 | ≤61.7pg/mL | 29 | 83 | 29 | 78 | 1.3 | 0.9 | 25 | ||
| 7αC4 | ≥52.5ng/mL | 29 | 78 | 33 | 79 | 1.7 | 0.8 | 25 | 82542 | 163 |
| Carbohydrate maldigestion | ||||||||||
| Fructose breath test | peak rise in breath H2>20 ppm | 98 | 86 | 26.9 | 99.9 | 7.0 | 0.02 | 26 | 91065 | 668.5 |
| Lactose breath test | peak rise in breath H2 >20 μL/L | 80 | 100 | 100 | 98.9 | ∞ | 0.2 | 27 | 91065 | 668.5 |
| Upper GI Motor Dysfunctions | ||||||||||
| Gastric Emptying of Solids at 4 hr with Scintigraphy | > 25% retention | 100 | 70 | 6.4 | 100 | 3.3 | 0 | 28 | ||
| Gastric Accommodation with SPECT | Accommodation ratio >3.0 | 40.6 | 95 | 52.5 | 92.1 | 8.1 | 0.6 | 29 | ||
CPT: Current Procedural Terminology; NPV: Negative predictive value; PPV: Positive predictive value; Sn: Sensitivity; Sp: Specificity; + LR: Positive likelihood ratio; −LR: Negative likelihood ratio.