Journal of Endocrinology and Metabolism, ISSN 1923-2861 print, 1923-287X online, Open Access |
Article copyright, the authors; Journal compilation copyright, J Endocrinol Metab and Elmer Press Inc |
Journal website http://www.jofem.org |
Original Article
Volume 2, Number 2, April 2012, pages 72-81
Clinical Validation of ELISA Assays for Insulin-Like Growth Factor-II (IGF-II)
Figures
Tables
Parameter | Mean | SD | Range |
---|---|---|---|
Age | 58.8 | 12.5 | 37 - 77 |
Weight (kg) | 68.2 | 14.9 | 37 - 102 |
Weight loss (% in 6 months) | 6.6 | 6.8 | 0 - 21 |
BMI (kg/m2) | 24.1 | 4.3 | 14.5 - 34.1 |
‘MUST’ score | 2.9 | 0.7 | 2 - 4 |
IGF-II (extraction ELISA) | IGF-II:IGF-I molar ratio | ||||||||
---|---|---|---|---|---|---|---|---|---|
r | P value | r | P value | ||||||
BMI (kg/m2) | 0.4523 | 0.0615 | 0.4606 | 0.0410* | |||||
% weight loss (last 6 months) | 0.2321 | 0.3248 | 0.2686 | 0.2521 | |||||
‘MUST’ score | 0.2820 | 0.2283 | 0.0392 | 0.8697 | |||||
Weight (kg) | 0.5206 | 0.0186* | 0.3950 | 0.0848 | |||||
IGF-II (non-extraction ELISA) | IGF-II:IGF-I molar ratio | ||||||||
r | P value | r | P value | ||||||
Pearson correlation analysis (r) was used for the IGF-II data and the IGF-II: IGF-I molar ratio. A two-tailed p-value was used to assess the significance of the correlation identified. * P < 0.05. | |||||||||
BMI (kg/m2) | 0.5131 | 0.0207* | 0.2814 | 0.2295 | |||||
% weight loss (last 6 months) | 0.1997 | 0.3985 | 0.2466 | 0.2947 | |||||
‘MUST’ score | 0.1541 | 0.5166 | -0.1521 | 0.5220 | |||||
Weight (kg) | 0.5370 | 0.0146* | 0.0848 | 0.7221 |
(a) Analyte | IGF-II (extraction ELISA) | IGF-II:IGF-I molar ratio | |||||||
---|---|---|---|---|---|---|---|---|---|
Rs | P value | rs | P value | ||||||
CRP | -0.2524 | 0.0248* | -0.3509 | 0.0016* | |||||
Albumin | 0.7032 | < 0.0001* | 0.3791 | 0.0007* | |||||
Creatinine | 0.1846 | 0.1034 | 0.1165 | 0.3098 | |||||
Urea | -0.0498 | 0.6629 | 0.0776 | 0.4993 | |||||
eGFR | 0.1837 | 0.1051 | 0.1949 | 0.0873 | |||||
ALP | -0.0834 | 0.4679 | 0.0905 | 0.4337 | |||||
ALT | 0.1593 | 0.1637 | 0.1323 | 0.2513 | |||||
aCa | -0.1124 | 0.3473 | -0.1347 | 0.2627 | |||||
(b) Analyte | IGF-II (non-extraction ELISA) | IGF-II:IGF-I molar ratio | |||||||
rs | P value | rs | P value | ||||||
Spearman rank correlation and two-tailed P-value were used (a) IGF-II measured using the extraction ELISA; (b) IGF-II measured using the non-extraction ELISA. * P < 0.05. Key: aCa, albumin-adjusted calcium; CRP, C-reactive protein; ALP, alkaline phosphatase; ALT, alanine transaminase; eGFR, estimated glomerular filtration rate. | |||||||||
CRP | -0.3007 | 0.0071* | -0.3194 | 0.0044* | |||||
Albumin | 0.7017 | < 0.0001* | -0.1318 | 0.2533 | |||||
Creatinine | 0.1632 | 0.1507 | -0.07349 | 0.5226 | |||||
Urea | -0.0187 | 0.8700 | 0.1718 | 0.1325 | |||||
eGFR | 0.1837 | 0.1051 | 0.1847 | 0.1054 | |||||
ALP | -0.1364 | 0.2338 | 0.1308 | 0.2568 | |||||
ALT | 0.1254 | 0.2740 | -0.0683 | 0.5550 | |||||
aCa | -0.05523 | 0.6449 | 0.0508 | 0.6739 |
Patient | Non-extraction ELISA | Extraction ELISA | RIA | |||
---|---|---|---|---|---|---|
IGF-II (nmol/L) | IGF-II:IGF-I molar ratio | IGF-II (nmol/L) | IGF-II:IGF-I molar ratio | IGF-II (nmol/L) | IGF-II:IGF-I molar ratio | |
IGF-II was measured using the extraction and non-extraction IGF-II ELISA’s in serum from patients with possible NICTH in whom IGF-II had previously been measured by RIA. Key: ND = not determined due to IGF-I concentration being below the detection limit for the immunoassay (< 3.2 nmol/L). False positive and negative results are shown in bold and bold italics, respectively. | ||||||
1 | 140.0 | 30.4 | 85.3 | 18.6 | 44.2 | 9.6 |
2 | 161.4 | 17.9 | 177.7 | 19.7 | 89.0 | 9.9 |
3 | 69.5 | 20.4 | 12.4 | 3.7 | 25.4 | 7.3 |
4 | 270.9 | 13.8 | 196.9 | 10.0 | 74.8 | 3.8 |
5 | 232.8 | ND | 246.7 | ND | 83.4 | ND |
6 | 121.5 | 35.7 | 49.2 | 14.5 | 92.8 | 27.3 |
7 | 233.4 | ND | 159.4 | ND | 81.0 | ND |
8 | 196.1 | 47.8 | 66.7 | 16.3 | 129.2 | 31.5 |
9 | 281.1 | 72.1 | 187.7 | 48.1 | 120.7 | 30.9 |
10 | 235.4 | 31.0 | 65.8 | 8.7 | 168.5 | 22.2 |