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10.5. Choice of reference interval

Chapter 10

Binding Site recommends that users either establish their own local HLC reference intervals, or validate an existing reference interval. The interpretation of HLC assays is further discussed in Chapter 11.

It is notable that the reference intervals for the HLC ratio for each immunoglobulin specificity are consistently different, suggesting that each immunoglobulin isotype makes use of a different repertoire of light chains. Thus, the median value for the IgGκ/IgGλ ratio is 2.0 compared with IgAκ/IgAλ and IgMκ/IgMλ ratios of 1.4 and 1.6, respectively [127].

There are no published studies that investigate the influence of age, gender and ethnic background on HLC concentrations or ratios. Hevylite concentrations in other biological fluids such as urine and CSF have yet to be studied. Clearly, in any fluid, the sum of the concentrations of each Hevylite pair should equal the total immunoglobulin levels but the ratio of Ig’κ to Ig’λ may differ from that found in serum.

Questions

  1. What evidence suggests that each immunoglobulin isotype makes use of a different repertoire of light chains?

Answers

  1. The reference intervals for the HLC ratio for each HLC specificity is different (Section 10.5).
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