Long-term storage of blood samples as whole blood at extremely low temperatures for methemoglobin determination.
Changes in methemoglobin (Met-Hb) concentrations during storage of whole blood and a hemolysate at refrigerated or various freezing temperatures were examined using experimentally prepared blood samples. When whole blood was stored at 3 degrees C, rapid reduction of Met-Hb was observed in the nitrite-treated blood whereas neither reduction nor formation of Met-Hb was observed in the untreated and heated blood within 7 days. When hemolysate was stored at 3 degrees C, Met-Hb concentrations were stable within a few days regardless of the initial values. However, slight autoxidation was observed 7 days after storage in the untreated and heated blood. When whole blood was stored at various freezing temperatures, Met-Hb concentrations were practically stable until at least 30 days at -80 degrees C or -196 degrees C regardless of the initial values, although considerable autoxidation was observed at -30 degrees C especially in the blood containing small amounts of Met-Hb. Based on the results obtained, a new method was devised for long-term storage of whole blood at extremely low temperatures for Met-Hb determinations.
Sato
K
K
Department of Legal Medicine, Nagoya University School of Medicine, Japan.
Tamaki
K
K
Okajima
H
H
Katsumata
Y
Y
D001793:Blood Preservation; D005615:Freezing; D006801:Humans; D008706:Methemoglobin / Q000032:analysis*; D010084:Oxidation-Reduction; D012016:Reference Values; D013053:Spectrophotometry; D013997:Time Factors
D008706:Methemoglobin