Martina Zaninotto

In the early 2000s an assay that measured

serum immunoglobulin-free light chains

(FLC) was developed

….these novel polyclonal antibodies

reacted with only those epitopes that were

hidden when bound to heavy chain but

available when not associated with heavy

chain

…the serum FLC assay in combination with

serum PEL and serum IFE is sufficient to

screen for pathological monoclonal plasma

Proliferative disorders other than AL…

-20

-15

-10

-5

0

5

10

15

20

CV

%

Mean = 18.19 mg/L

mean CV% =7.05 2008-2009

2014

2014

2012

What are the requirements of anti-FLC antibodies?

What are the desirable performance goals?

Why is there a lack of harmonisation of patient results?

What are the optimal sample dilution procedures?

How do laboratories manage non harmonised measurement?

What reference intervals should be used?

……………………?

Biochimica Clinica, 2013

Specificity of selected monoclonal antibodies for FLC

moAb Kappa moAb Kappa

moAb lambda moAb lambda

● FLC kappa

○ IgG1 kappa

● FLC lambda

○ IgG1 lambda

te Velthius H et al 2011

No

cross-reaction with intact

immunoglobulins

Monoclonal antibody

based-method

Policlonal antibody based-

method (Robson E et al, 2007)

(te Velthius H et al, 2011)

ETF Policlonal A Monoclonal A

K light chains MM

IgA K MM

IgA K MM

IgA K MM

Tate J et al, 2013

Pretorius CJ et al 2012

Controlli Freelite N latex

Low High Low High

media, mg/L

Kappa

CV %

15.92 29.35 14.00 34.87

5.8 9.7 7.5 11.9

media, mg/L

Lambda

CV %

28.22 60.38 11.92 32.20

8.5 9.6 3.6 4.8

Braga et al 2012

Hansen CT et al, 2014

CVi 4.3%, CVa 7.3% RCV 24% CVi 7.0%, CVa 4.5% RCV 23%

Is the assays comparable in

EQA schemes?

kappa

Distribution n ALTM mg/L SD mg/L CV%

053 31 5.43 2.83 52.20

054 30 6.71 5.22 77.8

055 34 3.45 2.51 72.8

056 48 3914.41 2729.16 69.7

061 Beckman 4 23574.0 10228 43.4

061 Behring 20 57.1 29.2 51.1

063 Beckman 7 4965.14 1325.2 26.7

063 Behring 22 4464.55 1045.7 23.4

(2009)

Vercammen M, 2011

2013

FLC Kappa

23.000 mg/L

FLC lambda

57.000 mg/L

pre-reaction signal

main-reaction signal

threshold value

for pre-reaction

te Velthius H, 2011

Vercammen M, 2011

Jacobs JFM, 2011

Jacobs JFM, 2011

Kappa

mg/L

Lambda

mg/L

k/l Analizzatore

Altinier S et al

CCLM, 2010

4.52 –22.33 4.84 – 21.88 0.15 – 3.35 BNII, nefelometro

Freelite method

Katzmann JA et al

Clin Chem, 2002

3.3–19.4 5.7 – 26.3 0.26 – 1.65 BNII, nefelometro

Freelite method

Pattenden RJ

Ann Clin Biochem,

2007

4.1–41 11.6 – 45.7 0.3 – 1.3 BNII, nefelometro

Freelite method

Beetham R et al

Ann Clin Biochem

2007

9.4-18.7 20.1 – 34.7 0.21 – 1.40 Image, nefelometro

Freelite method

Pattenden RJ

Ann Clin Biochem

2007

6.2–35.3 2.7 – 20.6 0.7 – 3.4 AU400 turbidimetro

Freelite method

Te Velthius H et al

CCLM , 2011

6.7-22.4 8.3-27.0 0.31 – 1.56 BN Systems

N Latex method

Tate J et al, 2013

0

20

40

60

80

100

120

140

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

L BS

L siemens

Cate

ne le

gg

ere

la

mb

da

,

mg

/L

Freelite

N_Latex

Autotrapianto

2007

Sospensione

Terapia 2009

POEMS + amiloidosi cardica

Monitoraggio 2007-2011

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

27

22

Ca

ten

e le

gg

ere

la

mb

da

,

mg

/L

POEMS + amiloidosi cardica

Monitoraggio 2007-2011

0,00

0,50

1,00

1,50

2,00

2,50

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Ka

pp

a/l

am

bd

a r

ati

o

POEMS + amiloidosi cardiaca

Monitoraggio 2007-2011

Freelite

N-Latex

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7

K BS

K siemens

Mieloma micromolecolare K

Monitoraggio 2007-2010

Ca

ten

e le

gg

ere

ka

pp

a,

mg

/L

Autotrapianto

2007

Freelite

N Latex

0

20

40

60

80

100

120

140

160

1 2 3 4 5 6

0

20

40

60

80

100

120

1 2 3 4 5 6 7

Mieloma micromolecolare K

Monitoraggio 2007-2010

Kap

pa/L

am

bd

a r

ati

o

0

10

20

30

40

50

60

1 2 3 4 5 6

09-2009

01-2010

05-2010

Palladini G et al

Mollee P et al, 2013

Performance characteristics strongly affect the

clinical value of the test and

laboratory specialists have a duty to promote

the continuous improvement of analytical

quality specifications,

as well as

to recommend the appropriate clinical

interpretation/utilization of results obtained

with currently available assays...

M.Plebani, 2005

Right test

Best quality

Sensible request for good clinical

reasons

Expert interpretation by people who

are well trained

Continual evaluation of practice

Dr. Joanna Sheldon

Protein Reference Unit

St. George’s Hospital