Table 2.
Distribution of vitamin D-binding protein (DBP) measurements according to assay method and genotype
| LC-MS/MS | Monoclonal ELISA | Polyclonal ELISA | ||||
|---|---|---|---|---|---|---|
| N | Concentration ug/ml Median (IQR) Mean ± SD |
Concentration ug/ml Median (IQR) Mean ± SD |
% Difference from LC-MS/MS Median (IQR) |
Concentration ug/ml Median (IQR) Mean ± SD |
% Difference from LC-MS/MS Median (IQR) |
|
| Overall | 125 | 253.1 (227.4, 283.4) 256.3 ± 39.6 |
185.0 (115.5, 248.9) 187.5 ± 79.3 |
−28 (−50, −5) | 373.8 (337.7, 419.5) 377.7 ± 72.6 |
+50 (+33, +65) |
| 1f/1f | 22 | 262.1 (236.2, 283.4) 261.8 ± 36.8 |
90.9 (77.6, 94.3) 85.3 ± 14.0 |
−67 (−71, −64) | 369.7 (341.4, 405.1) 364.7 ± 64.2 |
+41 (+25, +60) |
| 1f/2 | 20 | 232.5 (207.1, 262.4) 241.8 ± 46.0 |
119.2 (108.3, 134.4) 121.0 ± 19.5 |
−49 (−55, −45) | 367.2 (294.4, 409.2) 364.4 ± 87.6 |
+41 (+35, +67) |
| 1s/1f | 20 | 284.4 (240.3, 312.0) 278.5 ± 40.8 |
210.4 (189.1, 226.2) 201.8 ± 41.7 |
−25 (−35, −20) | 395.7 (361.4, 448.5) 406.2 ± 69.2 |
+45 (+32, +67) |
| 1s/1s | 22 | 255.9 (237.2, 274.9) 256.4 ± 22.9 |
307.3 (273.7, 331.9) 303.5 ± 33.8 |
+19 (+9, +28) | 387.6 (359.2, 453.6) 400.9 ± 61.0 |
+54 (+48, +66) |
| 1s/2 | 19 | 266.5 (221.0, 286.3) 254.9 ± 41.9 |
234.9 (210.5, 258.7) 236.6 ± 36.8 |
−5 (−14, 0.5) | 353.5 (314.6, 382.3) 352.0 ± 77.5 |
+34 (+25, +56) |
| 2/2 | 22 | 238.1 (218.0, 275.1) 244.7 ± 40.0 |
172.4 (150.7, 199.2) 179.0 ± 31.9 |
−28 (−30, −25) | 354.0 (328.7, 414.2) 375.6 ± 67.6 |
+56 (+40, +65) |
| ANOVA or Kruskal-Wallis test of difference in DBP concentration by genotype: | ||||||
| P value | 0.02 | 0.0001 | 0.10 | |||
| Variation in DBP concentrations explained by genotype: | ||||||
| R2 | 0.09 | 0.85 | 0.07 | |||