Yazarlar : Fedele PL, Choy KW, Doery JC

Yayın : Pathology

Yayın Yılı : 2014

Pubmed Linki : http://www.ncbi.nlm.nih.gov/pubmed/24557291

Konu : Myelom

Literatür İçeriği :

 Myeloma prognostication is largely defined by the International Staging System (ISS) using serum beta-2 microglobulin (β2 M) and albumin results. Local EQA (RCPA-QAP) data showed substantial, method-dependant variations in β2 M results.

AIM:

: We determined the variability of different β2 M methods using patient samples, and whether this influences ISS prognostic scores.

METHODS:

β2 M stability after freeze-thawing was established first. Specimens (n = 21) were then sent frozen to three laboratories using different methods for β2 M [lab 1, nephelometric; lab 2, chemiluminescent immunoassay (CLIA); and lab 3, enzyme immunoassay (EIA)]. All laboratories use the same albumin method (bromocresol purple). Results were assessed using Passing-Bablok regression and concordance for ISS scores.

RESULTS:

Lab 1 produced β2 M results consistently higher than other laboratories (β2 MLab2 = 0.79xβ2 MLab1-0.09; β2 MLab3 = 0.70xβ2 MLab1+0.17). Only 12 of 21 (57%) of the ISS prognostic scores were concordant by all three laboratories. Compared to Lab1, ISS scores were classified one stage lower in five and seven patients by Lab 2 and Lab 3, respectively. One additional patient was classified as stage 3 by Lab 1 but stage 1 by Lab 3. Albumin methods aligned well and had minimal impact on ISS score.

CONCLUSION:

Results from different β2 M methods are highly variable and harmonisation is required. This study has important implications on the validity of ISS staging for myeloma.

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