131I in blood samples: a danger for professionals? A problem for immunoassays?
OBJECTIVE
Our objective was to investigate the safety of radioactive blood samples from patients receiving 131I and whether the radioactivity affects the validity of assays.


METHODS
First, the activity of samples from patients given 131I was measured by 3 methods and compared with the upper threshold. Then, pilot sera were spiked with 131I, and possible interference was investigated using 2 immunoradiometric assays.


RESULTS
The activity of 13 of the 15 samples was below the European limit; the other 2 samples were from patients with reduced renal clearance rates. No differences in thyroglobulin level or thyroid-stimulating hormone level were found between sera that were spiked with 131I and sera that were not.


CONCLUSIONS
These blood samples are safe because they contain negligible activity, and the use of radioimmunoassays or immunoradiometric assays on them produces reliable results.
Vialard-Miguel
Julie
J
Nuclear Medicine Department, University Hospital of Bordeaux and University Bordeaux 2, Bordeaux, France. julie.miguel@chu-bordeaux.fr
Georges
Agnès
A
Mazère
Joaquim
J
Ducassou
Dominique
D
Corcuff
Jean-Benoît
JB
D016477:Artifacts; D005060:Europe; D006282:Health Personnel; D006403:Hematologic Tests; D007457:Iodine Radioisotopes / Q000097:blood* / Q000627:therapeutic use; D016273:Occupational Exposure / Q000032:analysis*; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control; D011835:Radiation Protection / Q000379:methods; D011863:Radioimmunoassay / Q000379:methods*; D011874:Radiometry / Q000379:methods*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors
D007457:Iodine Radioisotopes