Table 2.

Summary of the analytical performance of some optical methods for creatinine detection.

Detection Method (Enzyme or Assay Used)	Linear Detection Range	Limit of Detection	Response Time	Ref.
Light diffraction (CD)	0.01–0.7 mM	6 µM	14 min	[43]
Chemiluminescence (H2O2-Co2+)	0.1–30 µM	0.07 µM	1 min	[44]
Colorimetry (uric acid-Hg2+-AuNPs)	1–12 µM	1.6 nM	5 min	[28]
Colorimetry (citrate-AuNPs)	0.1–20 mM	0.72 mM	24 min	[45]
Colorimetry-enzPAD (CNN + CTN + SOD)	0.22–2.2 mM	0.17 mM	11 min	[46]
Fluorescence (QDs-CD conj.)	0.3–5 mM	n.a.	3–4 min	[47]
Ratiometric fluorescence (CD)	0.1–1.0 mM	0.0325 mM	1–3 min	This work

CD: creatinine deiminase, AuNP: gold nanoparticles, CNN: creatininase, CTN: creatinase, SOD: sarcosine oxidase, QD: quantum dots, enz-PAD: enzyme paper-based analytical device.