Cell Mol Med Res

Cellular and Molecular Medicine Research, ISSN 2817-6359 online, Open Access

Article copyright, the authors; Journal compilation copyright, Cell Mol Med Res and Elmer Press Inc

Journal website https://cmmr.elmerpub.com

Original Article

Volume 000, Number 000, July 2025, pages 000-000

Screening for Light Chain Monoclonal Gammopathy of Undetermined Significance: Pseudo Epidemic Based on Current Diagnostic Criteria

**Table 1.** Categorization of Urine Immunofixation Analysis
UIFE	Age in years	Race	Gender
UIFE-0 specimens were from patients without any indication of monoclonal gammopathy, except isolated presence of monoclonal light chain in urine. UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy. UIFE-3 specimens were from patients with ambiguous results and UIFE-4 specimens were from one patient with polymorphus sarcoma. The number of specimens for which κ/λ ratio results were available are given in parentheses. UIFE: urine protein immunofixation electrophoresis.
UIFE-0 (with κ/λ ratio)	3,230 (1,740)	18 - 96	61.2	14.6	1,556	1,505	46	123	1,795	1,435
UIFE-1 (with κ/λ ratio)	1,723 (1,589)	27 - 97	65.3	11.3	695	972	18	38	780	943
UIFE-3	42
UIFE-4	3
Total UIFE	4,998

Table 1. Categorization of Urine Immunofixation Analysis

UIFE

Age in years

Race

Gender

Range

Average

White

Black

Hispanic

Other

Female

Male

UIFE-0 specimens were from patients without any indication of monoclonal gammopathy, except isolated presence of monoclonal light chain in urine. UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy. UIFE-3 specimens were from patients with ambiguous results and UIFE-4 specimens were from one patient with polymorphus sarcoma. The number of specimens for which κ/λ ratio results were available are given in parentheses. UIFE: urine protein immunofixation electrophoresis.

UIFE-0 (with κ/λ ratio)

3,230 (1,740)

18 - 96

61.2

14.6

1,556

1,505

123

1,795

1,435

UIFE-1 (with κ/λ ratio)

1,723 (1,589)

27 - 97

65.3

11.3

695

972

780

943

UIFE-3

UIFE-4

Total UIFE

4,998

**Table 2.** Numbers and Percentage of Specimens in the UIFE-0 Category With Available SFLC Levels (N = 1,740) With Monoclonal Light Chains in Groups With Various Ranges of κ/λ Ratios
		Kappa, N	Kappa, %	Lambda, N	Lambda, %
More than 80% of the specimens with associated serum κ/λ ratio of > 3.0 or 3.15 did not exhibit monoclonal light chains in urine, or any other evidence of a monoclonal lesion. ^aUIFE Neg for kappa specimen with κ/λ ratio 11.53, patient with cirrhosis and creatinine 2.17. ^bFurther breakdown and data on these seven specimens are presented below in Table 3. ^cAdditional data for this group are shown in Table 4. FMLC: free monoclonal light chain; MG: monoclonal gammopathy; SFLC: serum free light chain; UIFE: urine protein immunofixation electrophoresis; UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.
Total UIFE-0 with κ/λ ratio	1,740
κ/λ ratio of ≤ 0.25	7^b	0	0	3	42.9
κ/λ ratio of 0.26 to ≤ 1.65	1,133	8	0.7	13	1.1
κ/λ ratio of 1.66 to 2.99	547	13	2.4	1	0.2
κ/λ ratio of 3 to 353^c	53	10	18.8	0	0
κ/λ ratio of 3 to 10	46	4	8.7	0	0
κ/λ ratio of 10 to 353	7^a	6	85.7	0	0
κ/λ ratio 0.26 - 0.75	45	0	0	12	26.7

Table 2. Numbers and Percentage of Specimens in the UIFE-0 Category With Available SFLC Levels (N = 1,740) With Monoclonal Light Chains in Groups With Various Ranges of κ/λ Ratios

Kappa, N

Kappa, %

Lambda, N

Lambda, %

More than 80% of the specimens with associated serum κ/λ ratio of > 3.0 or 3.15 did not exhibit monoclonal light chains in urine, or any other evidence of a monoclonal lesion. ^aUIFE Neg for kappa specimen with κ/λ ratio 11.53, patient with cirrhosis and creatinine 2.17. ^bFurther breakdown and data on these seven specimens are presented below in Table 3. ^cAdditional data for this group are shown in Table 4. FMLC: free monoclonal light chain; MG: monoclonal gammopathy; SFLC: serum free light chain; UIFE: urine protein immunofixation electrophoresis; UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.

Total UIFE-0 with κ/λ ratio

1,740

κ/λ ratio of ≤ 0.25

7^b

42.9

κ/λ ratio of 0.26 to ≤ 1.65

1,133

0.7

1.1

κ/λ ratio of 1.66 to 2.99

547

2.4

0.2

κ/λ ratio of 3 to 353^c

18.8

κ/λ ratio of 3 to 10

8.7

κ/λ ratio of 10 to 353

7^a

85.7

κ/λ ratio 0.26 - 0.75

26.7

**Table 3.** Additional Laboratory Data for the Seven Instructive Specimens With κ/λ Ratio of ≤ 0.25
UIFE-0 with κ/λ ratio ≤ 0.25
^aSpecimens from same patient. One of the three urines without monoclonal lambda light chains was from a patient who had two urine specimens with monoclonal lambda light chain in urine; the serum specimens corresponding to the lambda monoclonal positive urine specimens had lower κ/λ ratios of 0.14 and 0.19 and higher urine protein levels, while the negative urine specimen was associated with a κ/λ ratio of 0.22 and lower total urine protein of ≤ 4.0 mg/dL. The negative result on UIFE for this patient was likely due to a combination low levels of free monoclonal lambda chains and a dilute urine that may not have been concentrated optimally. ^bThis specimen with κ/λ ratio of 0.22 and urine negative for monoclonal light chains was from a 21-year-old patient with acute myeloid leukemia treated with stem cell transplantation. FMLC: free monoclonal light chain; MG: monoclonal gammopathy; UIFE: urine protein immunofixation electrophoresis; UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.
Negative	0.11	3.54	33
Negative	0.12	2.24	1,221
Lambda^a	0.14	0.81	11
Lambda^a	0.19	0.89	5
Lambda	0.21	1.9	19
Negative^a	0.22	1.02	≤ 4
Negative^b	0.22	0.49	26

Table 3. Additional Laboratory Data for the Seven Instructive Specimens With κ/λ Ratio of ≤ 0.25

UIFE-0 with κ/λ ratio ≤ 0.25

UIFE

κ/λ ratio

Gamma globulin, g/dL

Urine protein, mg/dL

^aSpecimens from same patient. One of the three urines without monoclonal lambda light chains was from a patient who had two urine specimens with monoclonal lambda light chain in urine; the serum specimens corresponding to the lambda monoclonal positive urine specimens had lower κ/λ ratios of 0.14 and 0.19 and higher urine protein levels, while the negative urine specimen was associated with a κ/λ ratio of 0.22 and lower total urine protein of ≤ 4.0 mg/dL. The negative result on UIFE for this patient was likely due to a combination low levels of free monoclonal lambda chains and a dilute urine that may not have been concentrated optimally. ^bThis specimen with κ/λ ratio of 0.22 and urine negative for monoclonal light chains was from a 21-year-old patient with acute myeloid leukemia treated with stem cell transplantation. FMLC: free monoclonal light chain; MG: monoclonal gammopathy; UIFE: urine protein immunofixation electrophoresis; UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.

Negative

0.11

3.54

Negative

0.12

2.24

1,221

Lambda^a

0.14

0.81

Lambda^a

0.19

0.89

Lambda

0.21

1.9

Negative^a

0.22

1.02

≤ 4

Negative^b

0.22

0.49

**Table 4.** Data From Patients With κ/λ Ratio 3 to 353 Regarding Average Total Urine Protein, dK, Gamma Globulins and eGFR to Contrast the Findings in Specimens Positive for Kappa Monoclonal Light Chains and Those Negative by UIFE
UIFE-0 with κ/λ ratio 3 to 353
Specimens with monoclonal Kappa in urine had higher dK, lower gamma globulins, and higher eGFR. The higher total protein in negative specimens may have interfered with concentration of urine. eGFR: estimated glomerular filtration rate; FMLC: free monoclonal light chain; MG: monoclonal gammopathy; UIFE: urine protein immunofixation electrophoresis; UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.
Average total protein	74	173	< 0.23
Average dK	30.73	12.18	< 0.0092
Average γ globulin	0.92	1.82	< 0.01
eGFR	65.67	43.65	< 0.023

Table 4. Data From Patients With κ/λ Ratio 3 to 353 Regarding Average Total Urine Protein, dK, Gamma Globulins and eGFR to Contrast the Findings in Specimens Positive for Kappa Monoclonal Light Chains and Those Negative by UIFE

UIFE-0 with κ/λ ratio 3 to 353

Kappa UFLC

Negative UFLC

P value

Specimens with monoclonal Kappa in urine had higher dK, lower gamma globulins, and higher eGFR. The higher total protein in negative specimens may have interfered with concentration of urine. eGFR: estimated glomerular filtration rate; FMLC: free monoclonal light chain; MG: monoclonal gammopathy; UIFE: urine protein immunofixation electrophoresis; UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.

Average total protein

173

< 0.23

Average dK

30.73

12.18

< 0.0092

Average γ globulin

0.92

1.82

< 0.01

eGFR

65.67

43.65

< 0.023

**Table 5.** The Range of Total Urine Protein and the Number and Percentage of Specimens With Monoclonal Light Chains, Kappa or Lambda, in the UIFE-0 Group
UIFE in UIFE-0 and total urine protein, mg/dL
UIFE: urine protein immunofixation electrophoresis; UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.
≤ 4	270	0	0.0
5 - 10	972	11	1.1
11 - 15	377	5	1.3
16 - 20	213	6	2.8
21 - 25	156	6	3.8
26 - 30	126	3	2.4
31 - 7,408	1,108	37	3.19
Total	3,222	68	2.11

Table 5. The Range of Total Urine Protein and the Number and Percentage of Specimens With Monoclonal Light Chains, Kappa or Lambda, in the UIFE-0 Group

UIFE in UIFE-0 and total urine protein, mg/dL

Urine protein, mg/dL

Number

UIFE positive, N

UIFE positive, %

UIFE: urine protein immunofixation electrophoresis; UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.

≤ 4

270

0.0

5 - 10

972

1.1

11 - 15

377

1.3

16 - 20

213

2.8

21 - 25

156

3.8

26 - 30

126

2.4

31 - 7,408

1,108

3.19

Total

3,222

2.11

**Table 6.** UIFE Data for Specimens From Patients With or History of Monoclonal Gammopathy
UIFE-1 total 1,723 (light chain type unresolved = 49)^b
The number and percentage of specimens exhibiting monoclonal light chains in urine. ^a*Upper observed limits of κ/λ ratio for kappa and lambda chain lesions, respectively. ^bDespite a history of prior monoclonal gammopathy, the light chain type could not be ascertained from the records as many patients were referred to this institution for consideration of autologous bone marrow transplantation and the referral materials did not include the isotype of the involved immunoglobulin and one was not ascertained at this institution. ^cUIFE results did not display an unambiguous monoclonal light chain band, had a biclonal or oligoclonal pattern, or displayed heavy chain only. UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
Total UIFE-1 with κ/λ ratio	1,589
κ/λ ratio of < 0.25	222	0	0.0	186	83.8
κ/λ ratio of 0.26 to ≤ 1.65	532	47	8.8	108	20.3
κ/λ ratio of 1.66 to 3.0	257	65	25.3	9	3.5
κ/λ ratio of 3 to 8,285^a/317^a	478	393	82.2	0	0
Unresolved^c		25			26

Table 6. UIFE Data for Specimens From Patients With or History of Monoclonal Gammopathy

UIFE-1 total 1,723 (light chain type unresolved = 49)^b

Kappa, N

Kappa, %

Lambda, N

Lambda, %

The number and percentage of specimens exhibiting monoclonal light chains in urine. ^a*Upper observed limits of κ/λ ratio for kappa and lambda chain lesions, respectively. ^bDespite a history of prior monoclonal gammopathy, the light chain type could not be ascertained from the records as many patients were referred to this institution for consideration of autologous bone marrow transplantation and the referral materials did not include the isotype of the involved immunoglobulin and one was not ascertained at this institution. ^cUIFE results did not display an unambiguous monoclonal light chain band, had a biclonal or oligoclonal pattern, or displayed heavy chain only. UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

Total UIFE-1 with κ/λ ratio

1,589

κ/λ ratio of < 0.25

222

0.0

186

83.8

κ/λ ratio of 0.26 to ≤ 1.65

532

8.8

108

20.3

κ/λ ratio of 1.66 to 3.0

257

25.3

3.5

κ/λ ratio of 3 to 8,285^a/317^a

478

393

82.2

Unresolved^c

**Table 7.** Subtypes of Specimens From Patient With Lambda Chain Associated Monoclonal Gammopathy or History of Such Lesion
UIFE-1 lambda	Number
SFLC: serum free light chain; UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
Total specimens	658
Specimens with SFLC data	599
Lambda UIFE positive total	329
Lambda UIFE positive with SFLC	302
Neg UIFE for lambda	292
UIFE positive for kappa	5
Unresolved	27

Table 7. Subtypes of Specimens From Patient With Lambda Chain Associated Monoclonal Gammopathy or History of Such Lesion

UIFE-1 lambda

Number

SFLC: serum free light chain; UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

Total specimens

658

Specimens with SFLC data

599

Lambda UIFE positive total

329

Lambda UIFE positive with SFLC

302

Neg UIFE for lambda

292

UIFE positive for kappa

Unresolved

**Table 8.** Numbers and percentages of UIFE-1 Lambda Specimens Displaying Monoclonal Light Chains at Various κ/λ Ratio Categories
UIFE-1 lambda UIFE positive by κ/λ ratio, number and percentage
UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
κ/λ ratio ≤ 0.25	230	185	30.9
κ/λ ratio 0.26 to ≤ 0.75	120	64	10.7
κ/λ ratio 0.75 to ≤ 1.65	195	44	7.3
κ/λ ratio 1.66 to 3.1	54	9	1.5

Table 8. Numbers and percentages of UIFE-1 Lambda Specimens Displaying Monoclonal Light Chains at Various κ/λ Ratio Categories

UIFE-1 lambda UIFE positive by κ/λ ratio, number and percentage

κ/λ ratio

Total in category

Number positive

Percentage positive

UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

κ/λ ratio ≤ 0.25

230

185

30.9

κ/λ ratio 0.26 to ≤ 0.75

120

10.7

κ/λ ratio 0.75 to ≤ 1.65

195

7.3

κ/λ ratio 1.66 to 3.1

1.5

**Table 9.** Numbers and Percentages of UIFE-1 Lambda Specimens Displaying Monoclonal Light Chains in Various dL Categories
UIFE-1 lambda by net lambda (dL)
Lowest dL = -8.1 with positive UIFE; lambda total level 11.65; κ/λ ratio 1.7. Lowest observed dL = -20.34, UIFE was neg; highest dL with Neg UIFE = 324.33. Lowest lambda total with pos UIFE = 0.24 Urine IgG L. UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
dL ≤ 1	273	64	10.7
dL 1 - 2	30	16	2.7
dL 2 - 3	26	11	1.8
dL ≥ 3.0	270	214	35.7
dL 3 - 10	78	53	8.8

Table 9. Numbers and Percentages of UIFE-1 Lambda Specimens Displaying Monoclonal Light Chains in Various dL Categories

UIFE-1 lambda by net lambda (dL)

dL range

Number in category

Number positive

% positive

Lowest dL = -8.1 with positive UIFE; lambda total level 11.65; κ/λ ratio 1.7. Lowest observed dL = -20.34, UIFE was neg; highest dL with Neg UIFE = 324.33. Lowest lambda total with pos UIFE = 0.24 Urine IgG L. UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

dL ≤ 1

273

10.7

dL 1 - 2

2.7

dL 2 - 3

1.8

dL ≥ 3.0

270

214

35.7

dL 3 - 10

8.8

**Table 10.** Numbers and Percentages of UIFE-1 Lambda Specimens Displaying Monoclonal Light Chains in Various Categories by Total Urine Protein Levels
UIFE-1 lambda and total urine protein, mg/dL
The kappa marked with * was IgG kappa. Other kappas were monoclonal kappa light chain bands. UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
≤ 4.0	54	5	9.3
5 to 10	171	41 + 1K*	24.0
11 to 15	52	30 + 3K	57.7
16 to 20	42	23	54.8
21 to 25	42	22 + 1K	59.1
26 to 30	22	13	59.1
31 to 5,445	267	192	71.9

Table 10. Numbers and Percentages of UIFE-1 Lambda Specimens Displaying Monoclonal Light Chains in Various Categories by Total Urine Protein Levels

UIFE-1 lambda and total urine protein, mg/dL

Urine protein, mg/dL

Number in category

Number positive

% positive

The kappa marked with * was IgG kappa. Other kappas were monoclonal kappa light chain bands. UIFE: urine protein immunofixation electrophoresis; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

≤ 4.0

9.3

5 to 10

171

41 + 1K*

24.0

11 to 15

30 + 3K

57.7

16 to 20

54.8

21 to 25

22 + 1K

59.1

26 to 30

59.1

31 to 5,445

267

192

71.9

**Table 11.** Subtypes of Specimens From Patient With Kappa Chain Associated Monoclonal Gammopathy or History of Such Lesion, i.e., UIFE-1 Kappa
UIFE-1 kappa	Number
SFLC: serum free light chain; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
Total specimens	1,024
Specimens with SFLC data	946
Kappa UIFE positive total	544
Kappa UIFE positive with SFLC	502
Neg UIFE for kappa	450
UIFE positive for lambda	0
Unresolved	30

Table 11. Subtypes of Specimens From Patient With Kappa Chain Associated Monoclonal Gammopathy or History of Such Lesion, i.e., UIFE-1 Kappa

UIFE-1 kappa

Number

SFLC: serum free light chain; UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

Total specimens

1,024

Specimens with SFLC data

946

Kappa UIFE positive total

544

Kappa UIFE positive with SFLC

502

Neg UIFE for kappa

450

UIFE positive for lambda

Unresolved

**Table 12.** Numbers and Percentages of UIFE-1 Kappa Specimens Displaying Monoclonal Light Chains at Various κ/λ Ratio Categories
UIFE-1 kappa UIFE positive by κ/λ ratio, % from total of 946
^aPositive for both Kappa and Lambda monoclonal light chains with kappa being the dominant band. UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
κ/λ ratio ≤ 0.25	1	1^a	100.0
κ/λ ratio ≤ 0.75	19	1	5.3
κ/λ ratio ≤ 1.65	222	45	19.4
κ/λ ratio 1.66 to 2.99	162	104	63.6
κ/λ ratio 3 - 10	214	63	29.9
κ/λ ratio 10 - 8,285	328	290	88.4
κ/λ ratio 3 - 8,285	542	353	65.1

Table 12. Numbers and Percentages of UIFE-1 Kappa Specimens Displaying Monoclonal Light Chains at Various κ/λ Ratio Categories

UIFE-1 kappa UIFE positive by κ/λ ratio, % from total of 946

κ/λ ratio

Number in category

Number positive

Percentage positive

^aPositive for both Kappa and Lambda monoclonal light chains with kappa being the dominant band. UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

κ/λ ratio ≤ 0.25

1^a

100.0

κ/λ ratio ≤ 0.75

5.3

κ/λ ratio ≤ 1.65

222

19.4

κ/λ ratio 1.66 to 2.99

162

104

63.6

κ/λ ratio 3 - 10

214

29.9

κ/λ ratio 10 - 8,285

328

290

88.4

κ/λ ratio 3 - 8,285

542

353

65.1

**Table 13.** Numbers and Percentages of UIFE-1 Kappa Specimens Displaying Monoclonal Light Chains in Various dK Categories
UIFE-1 kappa by net kappa (dK)
Lowest dK = -44.72 with positive UIFE; kappa total level 6.46; κ/λ ratio 0.13. Lowest observed dK = -44.72, UIFE was positive for both kappa and lambda. Highest dK with Neg UIFE = 317.3. Lowest kappa total with pos UIFE = 0.23 Urine IgG kappa. UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
dK ≤ 1	296	61	20.6
dK 1 - 2	103	28	27.2
dK 2 - 3	66	29	43.9
dK 3.0 - 6,280	483	384	79.5
dK 3 - 10	162	92	56.8

Table 13. Numbers and Percentages of UIFE-1 Kappa Specimens Displaying Monoclonal Light Chains in Various dK Categories

UIFE-1 kappa by net kappa (dK)

dK range

Number in category

Number positive

% positive

Lowest dK = -44.72 with positive UIFE; kappa total level 6.46; κ/λ ratio 0.13. Lowest observed dK = -44.72, UIFE was positive for both kappa and lambda. Highest dK with Neg UIFE = 317.3. Lowest kappa total with pos UIFE = 0.23 Urine IgG kappa. UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

dK ≤ 1

296

20.6

dK 1 - 2

103

27.2

dK 2 - 3

43.9

dK 3.0 - 6,280

483

384

79.5

dK 3 - 10

162

56.8

**Table 14.** Numbers and Percentages of UIFE-1 Kappa Specimens Displaying Monoclonal Light Chains in Various Categories by Total Urine Protein Levels
UIFE-1 kappa; total urine protein, mg/dL, N = 1,024
UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.
≤ 4	94	7	7.4
5 to 10	259	69	26.6
11 to 15	114	47	41.2
16 to 20	87	56	64.4
20 to 25	56	40	71.4
26 to 30	40	28	70.0
31 to 4,880	374	297	79.4

Table 14. Numbers and Percentages of UIFE-1 Kappa Specimens Displaying Monoclonal Light Chains in Various Categories by Total Urine Protein Levels

UIFE-1 kappa; total urine protein, mg/dL, N = 1,024

Urine protein, mg/dL

Number in category

Number positive

% positive

UIFE-1 specimens were from patients with extant monoclonal gammopathy or history of monoclonal gammopathy.

≤ 4

7.4

5 to 10

259

26.6

11 to 15

114

41.2

16 to 20

64.4

20 to 25

71.4

26 to 30

70.0

31 to 4,880

374

297

79.4

**Table 15.** Regression Report for UIFE-0
	Estimate	Std. error	z value	U Pr. (> \|z\|)
(Intercept)	-4.678425	0.279579	-16.734	< 2 × 10^-16***
U Pr.	-0.006437	0.00261	-2.466	0.0137*
Lambda	0.088108	0.021271	4.142	3.44 × 10^-5***
Ratio	0.52679	0.097425	5.407	6.40 × 10^-8***
To improve the diagnosis accuracy, we fitted a multivariable logistic regression that includes urine protein (U Pr.), lambda and kappa/lambda ratio as independent variables. P < 0.05; **P < 0.001. UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.
UIFE_Neg	1,693	0
UIFE_Pos	40	6

Table 15. Regression Report for UIFE-0

Estimate

Std. error

z value

U Pr. (> |z|)

(Intercept)

-4.678425

0.279579

-16.734

< 2 × 10^-16***

U Pr.

-0.006437

0.00261

-2.466

0.0137*

Lambda

0.088108

0.021271

4.142

3.44 × 10^-5***

Ratio

0.52679

0.097425

5.407

6.40 × 10^-8***

Number of positive and negative predictions (prediction accuracy rate is 0.977)

Prediction_Neg

Prediction_Pos

To improve the diagnosis accuracy, we fitted a multivariable logistic regression that includes urine protein (U Pr.), lambda and kappa/lambda ratio as independent variables. *P < 0.05; ***P < 0.001. UIFE-0: specimens from patients without evidence or history of MG, except solitary finding of FMLC in urine.

UIFE_Neg

1,693

UIFE_Pos