The development of a new reference range for fructosamine for the pathcare pathology group, Somerset West, South Africa

Abstract

Fructosamine is a generic name given to a compound known as plasma protein ketoamines. It is formed by a non-irreversible enzymatic reaction between glucose and serum proteins, mainly albumin. Fructosamine together with glycated haemoglobin (HbA1c) are used to monitor the state of hyperglycaemia in diabetics. It provides the clinician with an index of glycaemia over a shorter period of time than HbA1c, about 4 weeks due to the high turnover of human serum albumin in blood and the degree of glycation in serum proteins. The evolvement of automation in Clinical Chemistry necessitates that each pathology laboratory provides relevant sets of reliable reference values that are population and analyzer or method specific. Currently, the reference range for fructosamine at PathCare ranges between 200 to 285 μmol/L. Four hundred and forty six (120 white females, 117 white males, 114 mixed ancestry females, 95 mixed ancestry males) apparently healthy participants visiting the PathCare, Somerset West practice, were recruited for this study. Fructosamine, random blood glucose, HbA1c, total protein, albumin, and lipid profile was preformed on all individuals. Nonparametric methods, whereby the sample 2.5 and 97.5 percentiles are used to form the 95% reference interval, were used to determine the reference values for fructosamine. Though no significant differences (p = 0.086) were observed between males and females in the total population group the mixed ancestry males had significantly higher fructosamine levels (p = 0.01) compared to their female counterparts. The reference range of the entire sample was 223 – 295 μmol/L, however differed in the different population groups (white females = 228 - 291 μmol/L, white males= 223 – 296 μmol/L, mixed ancestry females = 217 - 293 μmol/L and mixed ancestry males = 222 – 304 μmol/L). The new fructosamine reference range obtained in this study showed a significant difference than the one used at Pathcare, which is 200 – 285 μmol/L. Our results further strengthen the recommendations by pathology bodies that laboratories must establish reference values that are representative of local populations. The single reference range (226 - 293 μmol/L) for the Caucasian males and females is recommended, however due to the significant differences observed between the mixed ancestry males and females it is recommended that gender specific references ranges be used for this population group, which are: 1) 222 - 304 μmol/L for the mixed ancestry males and 2) 217 - 293 μmol/L for the mixed ancestry females respectively.