Table 3 Novel reference intervals for serum kappa FLC (mg/L), serum lambda FLC (mg/L), and FLC ratio in individuals with eGFR of 45–59, 30–44, and < 30 mL/min/1.73 m2.

From: Defining new reference intervals for serum free light chains in individuals with chronic kidney disease: Results of the iStopMM study

Group

0.5th percentile

 

99.5th percentile

 
 

Value

95% CI

Value

95% CI

Kappa (mg/L)

    

 eGFR 45–59

7.8

7.6–8.2

83.6

70.2–96.2

 eGFR 30–44

8.8

6.3–10.4

103.3

86.9–165.1

 eGFR < 30

11.7

11.1–17.0

265.1

133.4–304.2

Lambda (mg/L)

    

 eGFR 45–59

7.3

6.5–7.6

65.1

52.6–73.2

 eGFR 30–44

8.2

6.9–9.3

73.2

66.9–93.3

 eGFR < 30

12.6

10.2–14.1

150.9

115.5–173.4

FLC ratio

    

 eGFR 45–59

0.46

0.41–0.51

2.62

2.24–6.93

 eGFR 30–44

0.48

0.37–0.54

3.38

2.45–12.3

 eGFR < 30

0.54

0.53–0.61

3.30

2.27–10.9

  1. Central 99% reference intervals. eGFR Estimated glomerular filtration rate, FLC Free light chain, CI Confidence interval.
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