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10.4.1. Binding Site Hevylite reference intervals

Chapter 10

The first reference intervals for Hevylite assays were established in the Binding Site laboratories with prototype Hevylite reagents on the Siemens BN™II instrument, using different collections of normal serum samples. The results were published in a number of abstracts (Tables 10.1, 10.2 and 10.3) [230][231][232]. In each case, there was a good correlation between the sum of concentrations measured by pairs of HLC reagents and the relevant total immunoglobulin assay (regression coefficient ranged from 0.9 to 0.997) [230][231][232]. A publication by Bradwell et al. [127] followed, which contained HLC reference intervals that were based on a different set of normal samples, but again using prototype reagents. Summation of Ig’κ and Ig’λ HLC results for normal sera produced a good agreement with total immunoglobulin measurements for each HLC specificity.

Shortly after the publication by Bradwell et al. [230] finalised and fully validated HLC reagents became commercially available as CE-marked diagnostic tests for use on the Binding Site SPAPLUS® (a turbidimeter) and the Siemens BNII (a nephelometer) (Chapter 38). Each product insert contains reference intervals determined using the finalised HLC reagents, as well as a comparison of the concentrations determined by summated Ig’κ and Ig’λ HLC compared to total immunoglobulin assays for a range of normal and disease state sera; all showing good agreement. Examples are shown in Figure 9.9.

A summary of the results of these various reference range studies is shown in Tables 10.1, 10.2 and 10.3. From these results, it can be seen that, although there are differences between the various reference intervals for each of the Hevylite parameters, the variations are small. These are likely to reflect sampling variations (when different sets of samples are evaluated) and the use of different instruments which utilise alternative optical detection technologies, namely nephelometry and turbidimetry.

Publication IgGκ (g/L) IgGλ (g/L) IgGκ/IgGλ
(95% RI)
IgGκ/IgGλ
(99% RI)
Harding et al. 2009 [232]3.92 - 12.16 2.28 - 6.05 1.13 - 3.27
Bradwell et al. 2009 [127]4.23 - 12.18 2.37 - 5.91 1.26 - 3.20
IgG HLC product inserts:
SPAPLUS
3.84 - 12.07 1.91 - 6.74 1.12 - 3.21
IgG HLC product inserts:
BNII
4.03 - 9.78 1.97 - 5.71 0.98 - 2.75
Katzmann et al. 2013 [40]4.34 - 10.80 1.77 - 5.31 1.30 - 3.70
Katzmann et al. 2015 [38]4.34 - 10.80 1.77 - 5.31 1.17 - 3.61 1.06 - 4.46

Table 10.1. IgG Hevylite published reference intervals.

Publication IgAκ (g/L) IgAλ (g/L) IgAκ/IgAλ
(95% RI)
IgAκ/IgAλ
(99% RI)
Bradwell et al. 2008 [230]0.34 - 2.33 0.19 - 2.06 0.67 - 3.12
Harding et al. 2009 [231]0.51 - 2.48 0.43 - 1.74 0.79 - 2.17
Bradwell et al. 2009 [127]0.43 - 2.36 0.40 - 1.73 0.58 - 2.52
IgA HLC product insert:
SPAPLUS
0.57 - 2.08 0.44 - 2.04 0.78 - 1.94
IgA HLC product insert:
BNII
0.48 - 2.82 0.36 - 1.98 0.80 - 2.04
Katzmann et al. 2013 [40]0.53 - 2.62 0.38 - 1.81 0.70 - 2.20
Katzmann et al. 2015 [38]0.53 - 2.62 0.38 - 1.81 0.70 - 2.21 0.53 - 2.52

Table 10.2. IgA Hevylite published reference intervals.

Publication IgMκ (g/L) IgMλ (g/L) IgMκ/IgMλ
(95% RI)
IgMκ/IgMλ
(99% RI)
Bradwell et al. 2009 [127]0.33 - 1.54 0.20 - 1.10 0.81 - 2.52
IgM HLC product insert:
SPAPLUS
0.19 - 1.63 0.12 - 1.01 1.18 - 2.74
IgM HLC product insert:
BNII
0.29 - 1.82 0.17 - 0.94 0.96 - 2.30
Guitarte et al. 2012 [234]
SPAPLUS
0.32 - 1.83 0.10 - 0.84 1.38 - 3.54
Guitarte et al. 2012 [234]
BNII
0.26 - 1.53 0.14 - 0.80 1.17 - 2.44
Katzmann et al. 2013 [40]0.22 - 1.43 0.10 - 0.94 1.00 - 2.40
Katzmann et al. 2015 [38]0.22 - 1.61 0.10 - 0.94 0.93 - 2.79 0.79 - 4.61
Boyle et al. 2016 [901]0.36 - 1.260.21 - 0.781.09 - 2.22

Table 10.3. IgM Hevylite published reference intervals.

A study using enzyme-linked immunosorbent assays (ELISAs) to measure Ig’κ/Ig’λ ratios (for IgG, IgA and IgM isotypes) in pooled normal sera reported median values that are similar to those obtained with the Hevylite assays [235]. This lends further support to the validity of the IgG HLC ratios determined by Hevylite assays.

Figures

References