Table 2.
Unadjusted and FLOXICE algorithm adjusted plasma glucose (mmol/L) measured by standard laboratory procedures compared to FLOXICE protocol in ORCHID time-course participants.
| OGTT Sample | OGTT by FLOXICE Protocol | OGTT by Standard Procedures | Standard OGTT Adjusted by FLOXICE Algorithm | |||
|---|---|---|---|---|---|---|
| PG | Delay to Analysis (h) | PG | PG Difference v FLOXICE Protocol | PG | PG Difference v FLOXICE Protocol | |
| Fasting | 4.9 ± 0.47 | 3.0 ± 0.4 | 4.5 ± 0.51 *** | −0.42 [−0.47 to −0.37] (−9.9% to −7.5%) |
4.9 ± 0.50 | 0.02 [−0.04 to 0.07] (−0.7% to 1.4%) |
| 1-h | 6.5 ± 1.76 | 2.0 ± 0.4 | 6.1 ± 1.67 *** | −0.38 [−0.47 to −0.28] (−6.8% to −4.8%) |
6.5 ± 1.64 | −0.01 [−0.12 to 0.10] (−1.1% to 1.8%) |
| 2-h | 5.8 ± 1.25 | 1.1 ± 0.4 | 5.6 ± 1.12 ** | −0.26 [−0.42 to −0.10] (−7.0% to −1.5%) |
5.8 ± 1.07 | −0.02 [−0.18 to 0.13] (−2.9% to 3.2%) |
FLOXICE = Fluoride-oxalate (FLOX) samples stored immediately on ice; ORCHID = Optimisation of Rural Clinical and Haematological Indicators for Diabetes in pregnancy study; PG = plasma glucose; OGTT = 75 g oral glucose tolerance test. Data include 12 participants with paired FLOXICE samples collected at the same time as their standard OGTT (1-h and 2-h samples, n = 11). Data are mean (± SD) for delay to analysis (h) and PG (mmol/L) and mean (95% CI: absolute (mmol/L) and proportional (%)) for difference in PG compared to samples processed by FLOXICE protocol. PG by standard procedures, unadjusted and algorithm adjusted, compared to FLOXICE protocol using students paired t-test. p-value < 0.01 **, < 0.001 ***. FLOXICE protocol: FLOX samples stored immediately on ice. Three aliquots, taken at 15 min, 30 min, and 45 min (< 1 h post-collection) were centrifuged for separation and immediate PG measurement. FLOXICE PG data is the mean glucose over the three < 1 h post-collection sample aliquots. OGTT by standard procedure for site: samples collected into FLOX tubes and stored and transported to laboratory at room temperature. Time of analysis of standard procedure samples was recorded and delay to analysis calculated from time of collection. Standard OGTT results were adjusted by linear regression β-coefficients for PG + delay-to-analysis + delay-to-analysis2 + constant, estimated for FLOXICE protocol PG using FLOXRT time-course data (Table A2).