Table 1.

Characteristics of included comparative studies

No	Study (year)	Population setting	Biomarker	Endpoint	AKI criteria	UOC	Total patient	No AKI (%)	AKI (%)	AKI severity	Timing of measurement
1	Qian et al. 2019 [24]	Patients who underwent cardiac surgery	Urinary NGAL Urinary Klotho	AKI within post-op 7 days	AKIN	No	91	58 (63.7)	33 (36.3)	AKI stage 1, 2, 3	Post-op 0, 2, 4 h
2	Prowle et al. 2015 [25]	Cardiopulmonary bypass, ICU patients	Urinary NGAL Urinary NGAL/Cr Urinary L-FABP	AKI within post-op 5 days	RIFLE	No	93	68 (73.1)	25 (26.9)	AKI stage R, I, F	Pre-op, and post-op 24 h
3	Lei et al. 2018 [26]	Decompensated cirrhosis	Urinary NGAL Urinary KIM-1 Serum CyC Serum Cr	AKI within 7 days	KDIGO	Yes	150	82 (54.7)	68 (45.3)	AKI stage 1, 2, 3	At hospital admission
4	van Wolfswinkel et al. 2016 [27]	Patients with imported falciparum malaria	Urinary NGAL Urinary KIM-1 Serum NGAL	AKI within 7 days	KDIGO	No	39	33 (84.6)	6 (15.4)	AKI stage 1, 2, 3	At hospital admission
5	Srisawat et al. 2015 [28]	Hospitalized patients with Leptospirosis	Urinary NGAL Serum NGAL	AKI within 7 days	KDIGO	No	113	71 (62.8)	42 (37.2)	AKI stage ≥ 1	At hospital admission
6	Zeng et al. 2014 [29]	Major surgery	Urinary NGAL Urinary L-FABP	Post-op AKI within 2 days	AKIN	No	197	160 (81.2)	37 (18.8)	AKI stage ≥ 1	Pre-op, and post-op 0, 4, 12 h and 1, 2, 7, 14 days
7	Aydoğdu et al. 2013 [30]	Critically ill patients with and without sepsis	Urinary NGAL Urinary CyC Serum CyC	AKI within 7 days	RIFLE	Yes	151	88 (58.3)	63 (41.7)	AKI stage R, I, F	Every day since ICU admission to the day of AKI
8	Liu et al. 2013 [31]	Cardiac surgery	Urinary NGAL Urinary L-FABP	Post-op AKI within 3 days	AKIN	No	109	83 (76.1)	26 (23.9)	AKI stage 1, 2, 3	Pre-op, and post-op 0, 2 h
9	Wagener et al. 2011 [32]	Orthotopic liver transplantation	Urinary NGAL/Cr	Post-op AKI within 7 days	RIFLE	No	92	55 (59.8)	37 (40.2)	AKI stage ≥ R	Pre-op, post-op 3, 18, 24 h
10	Makris et al. 2009 [33]	Critically ill multiple trauma patients	Urinary NGAL	AKI within 3 days	RIFLE	No	31	20 (64.5)	11 (35.5)	AKI stage R, I, F	At ICU admission and post-admission 24, 48 h
11	Constantin et al. 2010 [34]	Critically ill patients	Serum NGAL	AKI at ICU admission	RIFLE	No	88	36 (40.9)	52 (59.1)	AKI stage ≥ R	At ICU admission
12	Cruz et al. 2010 [35]	Critically ill patients	Serum NGAL	AKI during ICU stay	RIFLE	No	301	168 (55.8)	133 (44.2)	AKI stage R, I, F	Daily from ICU admission to 4 days after ICU admission
13	de Geus et al. 2011 [36]	Critically ill patients	Urine NGAL Serum NGAL	AKI with 7 days of ICU stay	RIFLE	No	632	461 (72.9)	171 (27.1)	AKI stage R, I, F	At ICU admission
14	Endre et al. 2011 [37]	Critically ill patients	Urinary NGAL/Cr Urinary CysC/Cr Urinary IL-18/Cr Urinary KIM-1/Cr	AKI, Mortality within 7 days	AKIN and RIFLE	No	528	381 (72.2)	147 (27.8)	AKI stage ≥ R or ≥ 1	At ICU admission, and at 12 and 24 h after admission
15	Breidthardt et al. 2012 [38]	Acute heart failure patients presented to emergency department	Serum NGAL	AKI	AKIN	No	207	147 (71)	60 (29)	AKI stage 1, 2, 3	Every 6 h from ER presentation to 48 h after ER
16	Camou et al. 2013 [39]	Critically ill adult with septic shock	Serum NGAL	AKI at ICU admission, and 24 h, 48 h	RIFLE/AKIN	No	50	7 (14)	43 (86)	AKI stage R, I, F, AKI stage 1, 2, 3	at ICU admission, and 24 h, 48 h
17	Doi et al. 2013 [40]	Cardiac surgical patients	Serum NGAL	AKI	AKIN	No	146	93 (63.7)	53 (36.3)	AKI stage ≥ 1	Pre-op, post-op 0, 2, 4, 12, 24, 36, 60 h
18	Gaipov et al. 2015 [41]	Cardiac surgical patients	Urinary NGAL Serum NGAL	Post-op AKI within 12 h, 24 h, 48 h and RRT	KDIGO	No	60	40 (66.7)	20 (33.3)	AKI stage 1, 2, 3, RRT	Post-op 2 h
19	Cuartero et al. 2019 [42]	Critically ill patients	Serum NGAL	AKI and ICU admission and 48 h later	AKIN and KDIGO	No	100	57 (57)	43 (43)	AKI stage 1, 2, 3	At ICU admission, and 24, 48 h later
20	Khawaja et al. 2019 [43]	Critically ill patients with suspected sepsis	Serum NGAL	Sepsis-related AKI	RIFLE	No	46	22 (47.8)	24 (52.2)	AKI stage ≥ R	12, 24, and 48 h after ICU admission
21	Mosa et al. 2018 [44]	Cardiothoracic surgery using cardiopulmonary bypass	Serum NGAL	Post-op AKI	KDIGO	No	182	117 (64.3)	65 (35.7)	AKI stage ≥ 1	Before CPB and at 0, 2, 12, 24 h after CPB
22	Sun et al. 2017 [45]	Scrub typhus-associated AKI	Serum NGAL Serum KIM-1 Urinary NGAL/Cr Urinary KIM-1/Cr	Scrub typhus–associated AKI	RIFLE	Yes	138	113 (81.9)	25 (18.1)	AKI stage R, I, F	Admission (n = 138) and 3 days after taking the initial sample (n = 37)
23	Ghonemy et al. 2014 [46]	Cardiac surgery (CPB & valve replacement surgery)	Serum NGAL Serum CysC	Post-op AKI	N.A	No	50	33 (66)	17 (34)	Creatinine level at 24 h being elevated either by 25% of the basal level or by 0.3 mg/dL above the basal level	Baseline, and post-op 3, 6, 24 h
24	Padhy et al. 2014 [47]	Patients received percutaneous coronary intervention	Serum NGAL Serum CysC	Contrast-induced AKI	N.A	No	60	30 (50)	30 (50)	by a rise in serum creatinine level of at least 0.5 mg/dL from the baseline value at 48 h	0, 4, 24, 48 h after coronary angiography
25	Geus et al. 2013 [48] (no sepsis)	ICU patients	Serum NGAL	AKI within 24 h after ICU admission	AKIN	No	542	427 (78.8)	115 (21.2)	AKI stage ≥ 1	ICU Admission (0 h) and at 4, 8, 24 h after ICU Admission
25	Geus et al. 2013 [48] (sepsis)	ICU patients	Serum NGAL	AKI within 24 h after ICU admission	AKIN	No	75	25 (33.3)	50 (66.7)	AKI stage ≥ 1	ICU Admission (0 h) and at 4, 8, 24 h after ICU Admission
26	Haase-Fielitz et al. 2009 [49]	Cardiac surgery	Serum NGAL, Serum CysC	Post-op AKI and 24 h after OP	SCr increase > 50% from baseline; RIFLE	No	100	77 (77)	23 (23)	AKI stage R, I, F	Baseline, post-op 6 h and 24 h
27	Hanson et al. 2011 [50]	Severe malaria	Urinary NGAL Serum Cr	RRT	N.A	No	163	79 (48.5)	84 (51.5)	RRT	On study enrollment
28	Introcaso et al. 2018 [51]	Cardiac surgery	Serum NGAL	Post-op AKI	KDIGO	Yes	69	45 (65.2)	24 (34.8)	AKI stage 1, 2, 3	Pre-op and within post-op 4 h in ICU
29	Kim et al. 2017 [52]	Critically ill patients with suspected sepsis	Serum NGAL Serum PENK	AKI, mortality	KDIGO	No	167	126 (75.4)	41 (24.6)	AKI stage ≥ 1, RRT	On study enrollment
30	Ferrari et al. 2019 [53]	Critically ill adult	Urinary TIMP-2 × IGFBP-7	AKI within 12 h, 24 h, 48 h and 7 days	KDIGO	Yes	442	254 (57.5)	188 (42.5)	AKI stage ≥ 1; RRT	ICU admission
31	Xie et al. 2019 [54]	ICU patients	Urinary TIMP-2 × IGFBP-7	CRRT, mortality, length of ICU stay	KDIGO Stage AKI 1, 2, 3	Yes	719	480 (66.8)	239 (33.2)	AKI stage ≥ 1	immediately upon enrollment
32	Adler et al. 2018 [55]	Out-of-hospital cardiac arrest	Urinary TIMP-2 × IGFBP-7	AKI	KDIGO Stage AKI 1, 2, 3	Yes	48	17 (35.4)	31 (64.6)	AKI stage ≥ 1	3 h and 24 h after OHCA
33	Oezkur et al. 2017[ 56]	Cardiac surgery	Urinary TIMP-2 × IGFBP-7	AKI within 48 h after op	KDIGO	Yes	100	80 (80)	20 (20)	Unknown	Before surgery (baseline), ICU admission (directly after Surgery), 24 h post-surgery
34	Wang et al. 2017 [57]	Cardiac surgery	Urinary TIMP-2 × IGFBP-7	AKI within 7 days after op	KDIGO	Yes	57	37 (64.9)	20 (35.1)	AKI stage 2 or 3	Before surgery, ICU admission (in 2-h intervals from 0 to 12 h after Surgery), 24 h after ICU admission
35	Finge et al. 2017 [58]	Cardiac surgery with cardiopulmonary bypass	Urinary TIMP-2 × IGFBP-7	AKI within 48 h after op	KDIGO	Yes	93	59 (63.4)	34 (36.6)	AKI stage ≥ 1	Before surgery and 3-h postoperative period
36	Cuartero et al. 2017 [59]	Septic and non-septic critically ill patients	Urinary TIMP-2 × IGFBP-7	AKI	AKIN	Yes	98	49 (50)	49 (50)	AKI stage ≥ 2, RRT	at ICU admission and up to 12 h later simultaneously with the morning blood work
37	Mayer et al. 2017 [60]	Cardiac surgery with cardiopulmonary bypass	Urinary TIMP-2 × IGFBP-7	Post-op AKI	KDIGO and RIFLE	Yes	110	101 (91.8)	9 (8.2)	AKI stage 1, 2, 3; stage R, I, F	Pre-op and at 1, 4, 24 h after surgery
38	Meersch et al. 2014 [61]	Cardiac surgery with cardiopulmonary bypass	Urinary TIMP-2 × IGFBP-7	Post-op AKI	AKIN or KDIGO	Yes	50	24 (48)	26 (52)	AKI stage 1, 2, 3	Pre-op and 4, 12, 24 h after CPB
39	Dusse et al. 2016 [62]	Cardiac surgery	Urinary TIMP-2 × IGFBP-7	AKI stage 2 or 3 within 48 h after op	KDIGO	Yes	40	32 (80)	8 (20)	AKI stage 2, 3	post-op 4 h and then twice daily until discharge from ICU (maximum 4 days)
40	Gunnerson et al. 2016 [63]	Critically ill patients	Urinary TIMP-2 × IGFBP-7	AKI stage 2 or 3	KDIGO	No	375	340 (90.7)	35 (9.3)	AKI stage 2, 3	Within 12 h of ICU admission
41	Wetz et al. 2015 [64]	Cardiac surgery	Urinary TIMP-2 × IGFBP-7	Post-op AKI Stage 1 or 2	KDIGO	No	42	26 (61.9)	16 (38.1)	AKI stage 1, 2	Baseline; End of surgery; 4 h after arrest of CPB; 1 day after surgery
42	Kimmel et al. 2016 [65]	ER patient	Urinary TIMP-2 × IGFBP-7	Positive U scores at enrollment		No	362	347 (95.9)	15 (4.41)	Unknown	Admission
43	Pilarczyk et al. 2015 [66]	Post-cardiac surgery	Urinary TIMP-2 × IGFBP-7	Post-op AKI stage 2 or 3 within 48 h	KDIGO	No	60	41 (68.3)	19 (31.7)	AKI stage 1,2,3	Post-op 4 h and every 12 h until discharge
44	Hoste et al. 2014 [67]	Critically ill patients	Urinary TIMP-2 × IGFBP-7	AKI stage 2 or 3 within 12 h	KDIGO	Partial	153	27 (17.6)	126 (82.4)	AKI stage 1,2,3	ICU admission
45	Cummings et al. 2018 [68]	Cardiac surgery	Urinary TIMP-2 × IGFBP-7	Post-op AKI stage 2 or 3 within 48 h	KDIGO	No	400	309 (77.3)	91 (22.7)	AKI stage 1, 2, 3	Immediately after CPB
46	Katagiri et al. 2012 [69]	Cardiac surgery	Urinary L-FABP	Post-op AKI	AKIN	No	77	49 (63.6)	28 (36.4)	Unknown	Pre-op, 0,4,12 h after ICU admission
47	Doi et al. 2011 [70]	Critically ill patients admitted to medical–surgical mixed ICU	Urinary L-FABP Urinary NGAL Urinary IL-18	AKI during admission	RIFLE	No	339	208 (61.4)	131 (38.6)	Unknown	12 h after ICU admission
48	Ferguson et al. 2010 [71]	Ordinary ward and ICU	Urinary L-FABP Urinary NGAL Urinary KIM-1Urinary IL-18 Urinary NAG	AKI	≥ 50% increase in SCr from baseline	No	160	68 (42.5)	92 (57.5)	unknown	NA
49	Li et al. 2012 [72]	Liver transplantation	Urinary L-FABP Urinary NGAL	AKI	AKIN	No	25	14 (56)	11 (44)	Unknown	0,2,4,6,12,24,48, 72,120 h after the anhepatic phase
50	Manabe et al. 2012 [73]	Cardiac catheterization	Urinary L-FABP	Contrast-induced AKI within 48 h	AKIN	No	220	201 (91.4)	19 (8.6)	Unknown	on day 0, 1 and 2 after contrast medium exposure
51	Matsui et al. 2012 [74]	Cardiac surgery	Urinary NGAL Urinary L-FABP	Post-op AKI within 48 h	AKIN	No	85	37 (43.5)	48 (56.5)	Unknown	Before OP, 0,3,6,18,24 and 48 h after OP
52	Khreba et al. 2019 [75]	Post-cardiopulmonary bypass in open heart surgery	Urinary KIM-1	Post-op AKI	KDIGO	No	45	18 (40)	27 (60)	Unknown	Post-op 3 h
53	Tu et al. 2014 [76]	Sepsis	Urinary KIM-1	Sepsis-related AKI	AKIN	No	150	101 (67.3)	49 (32.7)	Unknown	0,1,3,6,24,48 h after ICU admission
54	Parikh et al. 2005 [77]	ARDS	Urinary IL-18	AKI within the first 6 days of ARDS	Increase in SCr by at least 50%	No	138	86 (62.3)	52 (37.7)	Unknown	ICU admission 0,1,3 day
55	Parikh et al. 2004 [78]	Kidney transplant patients	Urinary IL-18	ATN	SCr from normal to > 3 mg/dL (> 265 umol/L)	No	72	50 (69.4)	22 (30.6)	Unknown	24 h after op
56	Han et al. 2009 [79]	Cardiac surgery	Urinary KIM-1/Cr	Post-op AKI within 72 h after surgery	AKIN	No	90	54 (60)	36 (40)	Unknown	0,3,18,24 h after op
57	Liangos et al. 2009 [80]	Cardiac surgery (Cardiopulmonary bypass)	Urinary KIM-1 Urinary NAG Urinary NGAL Urinary IL-18 Urinary CysC Urinary α1-microglobulin	Post-op AKI within 72 h	Cre inc > 50% in 72 h	No	103	90 (87.4)	13 (12.6)	Unknown	2 h
58	Naggar et al. 2012 [81]	Critically ill patients	Urinary KIM-1	AKI	RIFLE	No	40	20 (50)	20 (50)	Unknown	0,24,48 h
59	Nickolas et al. 2012 [82]	ER patients	Urinary KIM-1 Urinary NGAL Urinary IL-18 Urinary L-FABP Urinary CysC	AKI	RIFLE	No	1635	1539 (94.1)	96 (5.9)	Unknown	0 h ER
60	Vaidya et al. 2008 [83]	Inpatient nephrology consultation service	Urinary KIM-1 Urinary NGAL Urinary IL-18 Urinary HGF Urinary CysC Urinary NAG Urinary VEGF Urinary CXCL 10 Urinary Total protein	AKI	RIFLE	No	204	102 (50)	102 (50)	Unknown	0 h
61	Nisula et al. 2015 [84]	ICU patients	Urinary IL-18	AKI	KDIGO on Day 2 or Day 3	YES	1439	942 (65.5)	497 (34.5)	AKI Stage3 RRT	0-24 h
62	Nickolas TL et al. 2008 [85]	ER patients	Urinary NGAL Urinary NAG Urinary α1-microglobulin Urinary α1-acid glycoprotein	AKI	RIFLE-R	No	635	605 (95.3)	30 (4.7)	RRT	ED presentation
63	Cho et al. 2013 [86]	Critically ill patients admitted to medical–surgical mixed ICU	Urinary NGAL Urinary L-FABP	AKI	AKIN	No	145	91 (62.8)	54 (37.2)	AKIN stage 1,2,3 RRT	ICU admission
64	Park et al. 2019 [87]	Sepsis	Urinary NGAL	Sepsis-related AKI	KDIGO	No	140	121 (86.4)	19 (13.6)	Unknown	0 h
65	Perry et al. 2010[88]	Cardiac Surgical	Serum NGAL	Post-op AKI within 4 days	50% increase in serum	No	879	804 (91.5)	75 (8.5)	Unknown	0 h
66	Shapiro et al. 2010 [89]	Sepsis	Serum NGAL/Cr	AKI	AKI/ > 0.5 mg/dL in 72 h	No	661	637 (96.4)	24 (3.6)	RIFLE-I RIFLE-R	12,24,48,72 h
67	Thanakitcharu et al. 2014 [90]	Open cardiac surgery	Urinary NGAL	Post-op AKI	AKIN	No	130	84 (64.6)	46 (35.3)	Unknown	0,3,6 h after surgery
68	Valette et al. 2013 [91]	Contrast-induced	Serum NGAL	Contrast-related AKI within 72 h	AKIN	No	98	68 (64.6)	30 (35.4)	RRT	0,2,6,24 h
69	Varela et al. 2015 [92]	Cardiac surgery	Urinary NGAL	Post-op AKI	AKIN	No	66	50 (75.8)	16 (24.2)	Unknown	0,1,6,24 h after surgery
70	Chen et al. 2012 [93]	CCU, AMI	Serum NGAL, Urinary NGAL/Cr Urinary IL-18/Cr Urinary Cystatin C	AKI	AKIN	No	150	107 (71.3)	43 (28.7)	Unknown	after CCU admission
71	Nisula et al. 2014 [94]	Critically ill	Urinary NGAL	AKI < 72 h	KDIGO	No	1042	663 (63.6)	379 (36.4)	AKI Stage 1.2.3 RRT	ICU arrival, 12 h 24 h after admission
72	Maisel et al. 2016 [95]	Acute heart failure	Serum NGAL	Worsening renal function < 5 days	increase in plasma creatinine of 0.5 mg/dL or ≥ 50% above first value or initiation of acute renal replacement therapy	No	927	855 (92.2)	72 (7.8)	Unknown	Acute heart failure requiring intravenous diuretic agents. 2,6 h, 1,2,3d
73	Matsa et al. 2014 [96]	Critically ill	Serum NGAL Urinary NGAL	AKI < 72 h	RIFLE	No	194	135 (69.6)	59 (30.4)	Unknown	0,24,48,72 h ICU arrival
74	Munir et al. 2013 [97]	Cardiopulmonary bypass	Urine NGAL	Post-op AKI  < 48 h	AKIN	No	88	77 (87.5)	11 (12.5)	Unknown	4 h after CPB
75	Onk et al. 2016 [98]	Cardiac surgery	Serum IL-6 Serum NGAL Serum SCr	Post-op AKI  < 7 days	RIFLE	No	90	45 (50)	45 (50)	RIFLE-R,I,F	Pre-op 1,6,12,24,36 h,7d
76	AZRINA MD RALIB et al. 2017 [99]	Critically ill	Serum NGAL	AKI	KDIGO	No	225	138 (61.3)	87 (38.7)	Unknown	within 24 h of ICU admission
77	Yang et al. 2016 [100]	Heart failure	Urinary NGAL Urinary KIM-1 Urinary NGAL/Cr Urinary KIM-1/Cr Serum CysC	AKI	KDIGO	No	103	54	49	Unknown	Admission to ICU
78	Ueta et al. 2014 [101]	Endovascular stent graft repair of aortic aneurysm	Urinary NGAL/Cr Urinary NGAL Serum NGAL Serum L-FABP Serum L-FABP/Cr	Post-op AKI	AKIN	No	42	36	6	Unknown	2 h post-op 0 h, 2 h, 6 h, 1d, 3d, 4d
79	Chang et al. 2015 [102]	CCU patients	Urinary NGAL NGAL/Cr	Pre-renal and intrinsic AKI	KDIGO	No	147	76	71	Unknown	Admission to CCU
80	Hjortrup et al. 2014 [103]	ICU severe sepsis	Serum NGAL Urinary NGAL	AKI	KDIGO	No	222	191	31	AKI stage ≥ 1, RRT	On study enrollment
81	Chen et al. 2020 [104]	CCU patients	Serum IL-18 Serum NGAL Serum CysC Urinary NGAL Urinary NGAL/Cr	AKI	KDIGO	No	269	217	52	Unknown	Admission to CCU
82	Wybraniec et al. 2017 [105]	Contrast-induced acute kidney injury	Urinary KIM-1, Urinary IL-18	Contrast-induced AKI	KDIGO	No	95	86	9	Unknown	6 h after procedure
83	Sinkala et al. et al. 2016 [106]	Hospitalized patients	Urinary KIM-1	AKI	unknown	unknown	40	27	13	Unknown	Cross-sectional
84	Torregrosa et al. et al. 2014 [107]	Acute coronary syndrome or heart failure or undergoing coronary angiography	Urinary L-FABP Urinary KIM-1 Urinary NGAL	AKI	RIFLE	No	144	124	20	Unknown	12 h after procedure
85	Tekce et al. 2014 [108]	Patient received cisplatin	Urinary KIM-1, Serum KIM-1	AKI	Cre > 1.5–twofold	No	22	14	8	Unknown	Day 0, 1,3,5
86	Torregrosa et al. 2012 [109] (M)	Acute coronary syndrome	Urinary IL-18 Urinary NGAL	AKI	KDIGO		89	77	12	Unknown	12 h after procedure
86	Torregrosa et al. 2012 [109] (S)	Cardiac surgery	Urinary IL-18 Urinary NGAL	Post-op AKI	RIFLE, Cre inc > 50%	No	46	32	14	Unknown	12 h after surgery
87	Matsui et al. 2011 [110]	ICU patients	Urinary L-FABP/Cr Urinary NAG/Cr	AKI	AKIN (incre > 0.3, 50%)	No	25	11	14	Unknown	0 h after ICU
88	Parikh et al. 2011 [111]	Cardiac surgery	Serum NGAL Urinary NGAL Urinary IL-18	Post-op AKI	RIFLE	R	1219	1159	60	Unknown	0–5 day after surgery
89	Wang 2017 [112]	Cardiopulmonary bypass	Urinary IL-18	Post-op AKI	Cre increase > 50%	No	103	81	22	Unknown	Before CPB, at 2 h, 4 h, 6 h, 8 h and 12 h after CPB
90	Haase-Fielitz et al. 2009 [113]	Cardiac surgery	Serum NGAL	Post-op AKI	Cre increase > 50% within 168 h	No	100	77	23	RIFLE-I,F AKIN-2,3 RRT	6 h after start CPB
91	Waskowski 2021 [114]	Cardiac surgery	11. TIMP-2 × IGFBP-7: 0.3 12. TIMP-2 × IGFBP-7: 2	Post-op AKI	KDIGO	Yes	93	62 (67)	31 (33)	AKI stage ≥ 1	Post-op day 1
92	Imoto 2021 [115]	ICU patients	07. NGAL	AKI	KDIGO	Yes	106	35 (33)	71 (67)	AKI Stage 3	Day 1
93	Lee 2021 [116]	Cardiac surgery	05. L-FABP 06. L-FABP/Cr	Post-op AKI	KDIGO	Yes	144	85 (59)	59 (41)	AKI stage ≥ 1	Post-op 16–18 h
94	Szymanowicz 2021 [117]	Cardiac surgery	07. NGAL	Post-op AKI	KDIGO	No	114	96 (84)	18 (16)	AKI stage ≥ 1	3 h after OP
95	Zhen 2021 [118]	Acute coronary syndrome	09. Serum NGAL	AKI	AKIN	No	172	149 (87)	23 (13)	AKI stage ≥ 1	6 h after admission
96	Obata 2021 [119]	Open abdominal aortic aneurysm repair	06. L-FABP/Cr 08. NGAL/Cr	Post-op AKI	KDIGO	No	64	45 (70)	19 (30)	AKI stage ≥ 1	Pre-op, post-induction, 2 h post-AXC, Post-op, 4 h and 2 day
97	Qiu 2021 [120]	Sepsis	07. NGAL	Sepsis-related AKI	KDIGO	Yes	90	46 (51)	44 (49)	AKI stage ≥ 1	at ICU admission
98	Shakked 2022 [121]	COVID-19 patients	09. Serum NGAL	AKI	KDIGO	No	52	30 (58)	22 (42)	AKI stage ≥ 1, RRT	ER presentation
99	Vogel 2021 [122]	COVID-19 patients	04. KIM-1/Cr	AKI	KDIGO	No	54	46 (85)	8 (15)	AKI stage ≥ 1	ER presentation
100	Ergun 2021 [123]	Major surgery	09. Serum NGAL	Post-op AKI	AKIN	Yes	60	47 (78)	13 (22)	AKI stage ≥ 1	Pre-op, Post-op 6 h,24 h
101	Pilarczyk 2022 [124]	Thoracic aortic surgery	10. TIMP-2 × IGFBP-7: custom	Post-op AKI	KDIGO	Yes	101	74 (73)	27 (27)	AKI stage 2 or 3	Pre-op, Post-op 2 h, 6 h, POD 1
102	Okuda 2022 [125]	Emergency laparotomy	06. L-FABP/Cr	Post-op AKI	KDIGO	Yes	48	38 (79)	10 (21)	AKI stage ≥ 1	Pre-op, Post-op 2 h, 4 h, 6 h, 24 h, 48 h, 72 h
103	Pei 2022 [126]	Sepsis	09. Serum NGAL	Sepsis-related AKI	KDIGO	Yes	162	102 (63)	60 (37)	AKI stage ≥ 1	ER presentation
104	Jahaj 2021 [127]	ICU patients	09. Serum NGAL	AKI	RIFLE	Yes	266	168 (63)	98 (37)	AKI stage ≥ 1	24 h after ICU admission
105	Garms 2021 [128]	Patients received vancomycin	07. NGAL	Drug-related AKI	KDIGO	Yes	94	71 (76)	23 (24)	AKI stage ≥ 1	The first day of vancomycin use
106	Irqsusi 2021 [129]	Cardiac surgery	10. TIMP-2 × IGFBP-7: custom 11. TIMP-2 × IGFBP-7: 0.3 12. TIMP-2 × IGFBP-7: 2	Post-op AKI	KDIGO	Yes	50	36 (72)	14 ( (28)	AKI stage ≥ 1	Post-op 0.5 h, 1 h and 0, 6, 12, and 24 h after ICU admission
107	Guray 2021 [130]	Patients undergoing coronary angiography	09. Serum NGAL	Contrast-induced nephropathy	an increase of over 25% or equal to or over 44.2 μmol/L in baseline SCr at 48–72 h after cardiac catheterization	No	84	68 (81)	16 (19)	AKI stage ≥ 1	Before and at 4 and 24 h after the procedure
108	Tan 2022 [131]	Ureteroscopic lithotripsy-related urosepsis	01 IL-18 03. KIM-1 07. NGAL	Sepsis-related AKI	KDIGO	Yes	157	121 (77)	36 (23)	AKI stage ≥ 1	0, 4, 12, 24 and 48 h after the surgery
109	Lakhal 2021 [132]	Cardiac surgery patients	02. 11. TIMP-2 × IGFBP-7: 0.3	Post-op AKI	KDIGO	Yes	65	38 (58)	27 (42)	AKI stage ≥ 1	before CPB and post-CPB 6 h, 24 h
110	Sahu 2022 [133]	Patients undergoing percutaneous coronary intervention	03. 09. Serum NGAL	Contrast-induced nephropathy	an increase in SCr by > 0.5 mg/dL or > 25%, assessed at 48 h after the procedure	No	212	187 (88)	25 (12)	AKI stage ≥ 1	4 and 48 h after the procedure

AKI acute kidney injury, AKIN Acute Kidney Injury Network, ARDS acute respiratory distress syndrome, ATN acute tubular necrosis, CCU cardiac care unit, Cr creatinine, CPB cardiothoracic surgery using cardiopulmonary bypass, CysC cystatin C, ER emergency room, ICU intensive care unit, IL-18 interleukin-18, KDIGO Kidney Disease Improving Global Outcomes, KIM-1 kidney injury molecule-1, L-FABP liver-type fatty acid-binding protein, NGAL neutrophil gelatinase-associated lipocalin, PENK proenkephalin, RIFLE Risk, Injury, Failure, Loss, and End-stage renal disease, SCr serum creatinine, TIMP-2 × IGFBP-7 tissue inhibitor of metalloproteinases-2 × insulin-like growth factor-binding protein-7, UOC urine output criteria