Table 5f.
Portable fluorometers: device performance in bovine blood samples.
| Portable device vs. reference | iCheck Fluoro vs. HPLCa | iCheck Fluoro vs. HPLCa | iCheck Fluoro vs. HPLCa | iCheck Fluoro vs. HPLCa | iCheck Fluoro vs. HPLCb | ||||
|---|---|---|---|---|---|---|---|---|---|
| Vitamin A biomarker | Vitamin Ac | Vitamin Ac | Retinold | Vitamin Ac | Vitamin Ac | Retinold | Retinold | Retinold | Retinold |
| Sample type | Whole blood | Whole blood | Whole blood | Plasma | Plasma | Plasma | Plasma | Serum | Serum |
| Study population | 28 cows | 11 calves | 10 cows | 28 cows | 11 calves | 40 cows | 92 bulls | 29 cows | 32 black cattle |
| Concentration difference | Range: 184–336 | (see note)e | MD: −0.013 ± -0.020 | MD: 19.3 | MD: 26.5 | MD: 0.01 | MD: 0.00 | ||
| Correlation coefficient | 0.78 | 0.90 | 0.92 | 0.88 | 0.96 | 0.94 | 0.93 | ||
| R2 | 0.61 | 0.81 | 0.84 | 0.77 | 0.92 | 0.88 | g0.87 | ||
| 0.88 | 0.94 | ||||||||
| Regression equation | y = 0.77 + 11.26 | NR | y = 1.18x − 72.64 | y = 0.80x + 1.32 | NR | NR | |||
| y = 1.03–30.11 | |||||||||
| Operational range | NR | NR | NR | NR | NR | ||||
| VAD or VAI (%) | NR | NR | NR | NR | NR | NR | NR | NR | NR |
| Precision | |||||||||
| Sensitivity | NR | NR | States test is sensitive and specific but does not quantify these | NR | NR | States test is sensitive and specific but does not quantify these | States test is sensitive and specific but does not quantify these | States test is sensitive and specific but does not quantify these | States test is sensitive and specific but does not quantify these |
| Specificity | NR | NR | NR | NR | |||||
| Intra-assay %CV | NR | NR | NR | NR | NR | 2.3% vs. 5.3 %f | 2.1% vs. 3.3 %f | ||
| Inter-assay %CV | NR | NR | NR | NR | NR | ||||
| Inter-observer %CV | NR | NR | NR | NR | NR | NR | NR | NR | NR |
| Bland-Altman analysis comments | Good level of agreement and no systematic error. 5% of total values fell outside 95% acceptability limits | Good level of agreement and no systematic error; 4% of total values fell outside the 95% acceptability limits | Good level of agreement and no systematic error. 1 value fell outside of 95% acceptability limits | Good level of agreement and no systematic error. 1 value fell outside of 95% acceptability limits | Good level of agreement and no systematic error. 4% of values fell outside the 95% acceptability limits | ||||
| Reference | (Ghaffari et al., 2019) | (Raila et al., 2017) | (Ghaffari et al., 2019) | (Raila et al., 2017) |
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Notes:MD, mean difference; NR, not reported; RE, retinol equivalents defined as the sum of retinol and retinyl esters, equal to 3.3 International Units (IU) of vitamin A or as 1 µg (units reported by manufacturer—however, retinol activity equivalents (RAE) are the preferred unit for reporting (Institute of medicine, 2001); VAD, vitamin A deficiency; VAI, vitamin A insufficiency.
Reference sample is in plasma.
Reference sample is serum.
Units: µg RE/L.
Units: µmol/L.
Reported value from this study appears to be a repeated value for cow whole blood beta carotene content given as 2.09–8.15 mg/L, instead of the calf whole blood vitamin A reported in µg RE/L.
Values appear to be an average of intra- and inter-assay %CV.