Table 1. Comparison between the coverage in HMDB 1.0, 2.0, 3.0 and HMDB 4.0.
| Category | HMDB 1.0 | HMDB 2.0 | HMDB 3.0 | HMDB 4.0 |
|---|---|---|---|---|
| Total number of metabolites | 2180 | 6408 | 40 153 | 114 100 |
| Number of detected & quantified metabolites | 883 | 4413 | 16 714 | 18 557 |
| Number of detected, not quantified metabolites | 1297 | 1995 | 2798 | 3271 |
| Number of expected metabolites | 0 | 0 | 20 641 | 82 274 |
| Number of predicted metabolites* | 0 | 0 | 0 | 9548 |
| Number of unique synonyms | 27 700 | 43 882 | 199 668 | 1 231 398 |
| Number of cmpds with expt. MS/MS spectra | 390 | 799 | 1249 | 2265 |
| Number of cmpds with expt. GC/MS spectra | 0 | 279 | 1220 | 2544 |
| Number of cmpds with expt. NMR spectra | 385 | 792 | 1054 | 1494 |
| Number of cmpds with pred. MS/MS spectra* | 0 | 0 | 0 | 98 601 |
| Number of cmpds with pred. GC/MS spectra* | 0 | 0 | 0 | 26 880 |
| Number of experimental NMR spectra | 765 | 1580 | 2032 | 3840 |
| Number of experimental MS/MS spectra | 1180 | 2397 | 5776 | 22 198 |
| Number of experimental GC/MS spectra | 0 | 279 | 1763 | 7418 |
| Number of predicted MS/MS spectra* | 0 | 0 | 0 | 279 972 |
| Number of predicted GC/MS spectra* | 0 | 0 | 0 | 38 277 |
| Number of metabolic pathway maps | 26 | 58 | 442 | 25 570 |
| Number of compounds with disease links | 862 | 1002 | 3105 | 5498 |
| Number of compounds with concentration data | 883 | 4413 | 5027 | 7552 |
| Number of predicted molecular properties | 2 | 2 | 10 | 24 |
| Number of metabolite-SNP interactions* | 0 | 0 | 0 | 6777 |
| Number of metabolite-drug interactions* | 0 | 0 | 0 | 2497 |
| No. of metabolites w. sex/diurnal/age variation* | 0 | 0 | 0 | 2901 |
| Number of metabolic reactions* | 0 | 0 | 0 | 18,192 |
| Number of defined ontology terms* | 0 | 0 | 0 | 3150 |
| Number of HMDB data fields | 91 | 102 | 114 | 130 |
* New for HMDB 4.0