US EPA

5968154 

Journal Article 

Degradation of crystalline polyethylene glycol 6000 and its effect on assays for macroprolactin and other analytes 

Ellis, G 

2006 

Yes 

Clinical Biochemistry
ISSN: 0009-9120
EISSN: 1873-2933 

39 

10 

1035-1040 

English 

16854405 

10.1016/j.clinbiochem.2006.05.014 

WOS:000241447600013 

OBJECTIVES: To determine why the incidence of macroprolactinemia was increasing in our laboratory.

DESIGN AND METHODS: Serum macroprolactin was detected by treatment with polyethylene glycol 6000 (PEG 6000).

RESULTS: We compared results using freshly prepared solutions of PEG 6000 from various bottles of crystalline reagent and concluded that our stock had deteriorated. When decomposition was first suspected, the PEG 6000 caused a more complete precipitation of proteins, leading to poorer recovery of monomeric prolactin and false-positive macroprolactinemia, necessitating a 43-patient recall. After a further 6-8 months of decomposition, the PEG 6000 failed to fully precipitate macroprolactin, giving false-negative results. The PEG 6000 reacted strongly with Schiff's reagent (a test for aldehydes) throughout. Recoveries of several other analytes after PEG 6000 treatment were also affected.

CONCLUSIONS: PEG 6000 can deteriorate in the crystalline form, producing aldehydes and/or other compounds that denature serum proteins variably, causing false-positive or false-negative macroprolactin results.