Seven serial dilutions of this sample in hemolyzing
buffer (1 in 4 to approximately 1 in 20) were used to determine the range of readable area that produced a reliable Hb [A.sub.1c] result (see Fig.
(1) that the inclusion of a suitable hemolyzing
agent is a logical support to erythrocyte folate extraction.
To maximize the release of erythrocyte folate, and thus ensure appropriate measurement of folate status, it may be necessary to use a hemolyzing
agent within the RCF assay to ensure complete release of Hb.
The procedure begins with an autodiluter aspirating 5 [micro]L of blood and dispensing it with 1 mL of hemolyzing
CO-Oximetry interference by perflubron emulsion: comparison of hemolyzing
and nonhemolyzing instruments.
After the patients' blood samples were mixed manually with the hemolyzing
and other reagents for the IMx glycohemoglobin assay in the same proportions as are used in this analyzer, numerous intact leukocytes (lymphocytes) could be observed by microscopy.
Additives that did not have similar effects on ZPP/H included albumin and the hemolyzing
agents deoxycholate and saponin.
Therefore, we shall refer to these particular instruments as hemolyzing
For Hb [A.sub.1c] the hemolyzing
reagent is a pH 5.0 citrate buffer that also serves to remove the labile fraction.
According to our procedure there was no need for the glucose concentration to be known in advance; we stabilized the concentration by adding hemolyzing
agent at the same time that B-glucose concentration was being measured in the GP office.
Sample preparation involved dilution of 50 [micro]L of citrated whole blood to 1 mL with hemolyzing
reagent (10 mmol EDTA and 5 mmol KCN).
Samples were prepared by adding 45 [micro]L of whole blood to 2.5 mL of hemolyzing
solution (acid potassium phthalate 25 mmol/L; KCN 8 mmol/L; Triton X-100 10 mL/L, pH 5.5), mixed vigorously, sonicated (2 min), and then incubated for 45 min at 25 [degrees]C to eliminate the labile fraction.