Effects of sterilizing gamma irradiation on bloodspot newborn screening tests and whole blood cyclosporine and tacrolimus measurements.

Author(s): Stickle DF, McKenzie DA, Landmark JD, Pirruccello SJ, Post GR, Iwen PC, Thompson RB, Hinrichs SH

Publication: Am J Clin Pathol, 2003, Vol. 119, Page 292-7

PubMed ID: 12580001 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of a 100 h exposure to 18 kGy gamma irradiation, such as what would occur during mailing, on cyclosporine and tacrolimus concentrations in blood specimens. Non-irradiated specimens were put in plastic bags and placed next to the machine for the duration of irradiation. No specimens were actually mailed. All specimens were tested less than 48 h after irradiation.

   Summary of Findings:

   Tacrolimus concentrations showed an insignificant decline of 10% in gamma irradiated blood specimens. The authors hypothesize the decline was possibly due to the small specimen number (5) and/or the high interassay variance (11%). Cyclosporine concentrations in blood were not affected by gamma irradiation.

   Biospecimens

   • Bodily Fluid - Blood

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Not specified

   Platform:

   Analyte	Technology Platform
   Small molecule	Immunoassay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage conditions	With 18 kGy gamma irradiation Without irradiation
   Storage	Between site transportation method	Mailed Not transported

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2. Study Purpose

   The purpose of this study was to determine the effects of 100 h exposure to 18 kGy gamma irradiation, such as what would occur during mailing, on newborn blood screening results in dried blood spots. Non-irradiated specimens were put in plastic bags and placed next to the machine for the duration of irradiation. No specimens were actually mailed. All specimens were tested less than 48 h after irradiation. Blood spots for phenylalanine analysis were prepared using supplemented adult blood, and blood spots for thyrotropin were prepared from adult serum. All other blood spots were from routine newborn blood testing.

   Summary of Findings:

   A 9% decline in hyperphenylalaninemia was measured in the irradiated specimens (p=0.03). Gamma irradiation also caused levels of biotinidase and galactose-1-phosphate uridyltransferase to decrease by 40% and 50%, respectively (both, p<0.001), but even after irradiation, all specimens maintained levels necessary for proper clinical classification, so irradiation was clinically insignificant. T4 and thyrotropin levels also declined after irradiation by 27% and 32%, respectively (both, p<0.005), but the authors report decreases of this magnitude are unlikely to affect clinical diagnosis. While the hemoglobin genetic variant was properly identified in all specimens, the hemoglobin fast fraction was elevated, and the A and S fractions were decreased in irradiated specimens compared to non-irradiated specimens, which, the authors report, would flag the specimens for repeat testing in a clinical setting.

   Biospecimens

   • Bodily Fluid - Blood
   • Bodily Fluid - Serum

   Preservative Types

   • Other Preservative

   Diagnoses:

   • Not specified
   • Other diagnoses

   Platform:

   Analyte	Technology Platform
   Protein	Clinical chemistry/auto analyzer
   Protein	Colorimetric assay
   Protein	HPLC
   Peptide	Immunoassay
   Small molecule	Fluorometry

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Between site transportation method	Mailed Not transported
   Storage	Storage conditions	With 18 kGy gamma irradiation Without irradiation
   Preaquisition	Patient genotype	Hemoglobin F and A Heterozygous for beta chain hemoglobin variants

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