Table 3.

Results of sample site comparisons in ICU patients and healthy volunteers

	Estimate (Ratio)	95% CI	p-value
ICU patients
Finger LP2.1 vs Arterial LP2.1	1.47	1.29 to 1.68	< 0.001
Earlobe LP2.1 vs Arterial LP2.1	1.27	1.11 to 1.45	< 0.001
Finger LP2.2 vs Arterial LP2.2	1.85	1.55 to 2.21	< 0.001
Earlobe LP2.2 vs Arterial LP2.2	1.22	1.03 to 1.46	0.024
Finger LP2.1 vs Venous LP2.1	1.14	1.01 to 1.30	0.040
Earlobe LP2.1 vs Venous LP2.1	0.99	0.87 to 1.12	0.871
Finger LP2.2 vs Venous LP2.2	1.43	1.20 to 1.69	< 0.001
Earlobe LP2.2 vs Venous LP2.2	0.95	0.80 to 1.13	0.569
Healthy volunteers
Finger vs arterial	1.14	1.04 to 1.24	0.003
Earlobe vs arterial	0.98	0.90 to 1.06	0.568

The results presented in the table are based on mixed effects models with log transformed lactate as the dependent variable. The ratios presented are based on fixed effect coefficients, exponentially transformed to be interpretable as ratios. For example, lactate measurements from the fingertip are estimated as 47% higher than arterial measurements in ICU patients