Table 3.
Unadjusted and adjusted FC Mix algorithm plasma glucose (mmol/L) measured by standard laboratory procedures compared to FC Mix protocol in ORCHID time-course participants.
| OGTT Sample | OGTT by FC Mix Protocol | OGTT by Standard Procedures | Standard OGTT Adjusted by FC Mix Algorithm | |||
|---|---|---|---|---|---|---|
| PG | Delay to Analysis (h) | PG | PG Difference v FC Mix Protocol | PG | PG Difference vs. FC Mix Protocol | |
| Fasting | 5.1 ± 0.47 | 3.0 ± 0.4 | 4.5 ± 0.51*** | −0.62 [−0.67 to −0.56] (−13.6% to −10.9%) |
5.1 ± 0.50 | −0.01 [−0.06 to 0.05] (−1.3% to 1.0%) |
| 1-h | 6.8 ± 1.88 | 2.0 ± 0.4 | 6.1 ± 1.67*** | −0.63 [−0.84 to −0.43] (−11.3% to −7.1%) |
6.8 ± 1.74 | −0.01 [−0.21 to 0.18] (−2.2% to 2.8%) |
| 2-h | 6.0 ± 1.28 | 1.1 ± 0.4 | 5.6 ± 1.12** | −0.49 [−0.73 to −0.26] (−10.8% to 4.2%) |
6.0 ± 1.28 | −0.03 [−0.20 to 0.14] (−3.1% to 3.5%) |
FC Mix = Fluoride-citrate-EDTA samples stored at room temperature; 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 FC Mix 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 FC Mix protocol. PG by standard procedures compared to FC Mix protocol using students paired t-test. p-value < 0.01 **, < 0.001 ***. FC Mix protocol: FC Mix samples stored at room temperature. Five aliquots taken at 0.25 h, 0.5 h, 0.75 h, 1 h, and 4 h post-collection were centrifuged for plasma separation and immediate PG measurement. FC Mix PG data is the mean glucose over the five sample aliquots. OGTT by standard procedure for site: samples collected into fluoride-oxalate 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 FC Mix protocol PG using FLOX RT time-course data (Table A2).