Storage and stability of folate and vitamin B-12 in plasma and blood samples

Storage of Human Biospecimens: Selection of the Optimal Storage Temperature

“…77 In another study, Panesar et al 78 measured the levels of thyroid hormones (TSH, fT4, and fT3) after 8-11 years of storage at -80°C and found a decrease in TSH and an increase in fT3 and fT4 concentrations with storage times. Kubasik et al 79 examined the effects of duration and temperature of storage on 14 different analytes in serum which are often used for radioimmunoassay procedures. They found that the analytes cholylglycine, cortisol, digoxin, ferritin, follitropin, immunoglobulin E, lutropin, prolactin, thyroxin, and triiodothyronine were stable for 2 weeks at room temperature.…”

“…However, insulin and gastrin were less stable and needed to be refrigerated or stored at -70°C, respectively. 79 The stability of purified and nonpurified forms of nucleic acids has also been studied. Vindeløv et al 80 investigated the effects of storage for 1 year at -80°C on DNA extracted from JB-1 tumor cells and fine-needle aspirates of solid tumor tissue.…”

Effects of Delayed Sample Processing and Freezing on Serum Concentrations of Selected Nutritional Indicators

“…Most reported studies have been limited in scope to single or few analytes (3)(4)(5)(6)(7)(8) or to particular panels, such as antioxidant (pro)vitamins (9 -12 ). Only a few studies have evaluated the effects of preanalytical factors on a broader list of nutritional indicators (13)(14)(15), and all but one of these studies (14 ) have had small sample sizes (12 individuals or fewer).…”

Vitamin B12 and Folate Status of a Selected Group of Free-Living Older Persons

“…Stability of folate and vitamin B,, in plasma for this length of time has been established (Kubasik et al, 1979). On the day that blood was taken, subjects were asked to restrict breakfast to toast, j h , jelly or honey, and black coffee or tea, with or without sugar.…”