Class of organic compounds
Fructosamines
are compounds that result from
glycation
reactions between glucose and a
primary amine
, followed by
isomerization
via the
Amadori rearrangement
. Biologically, fructosamines are recognized by
fructosamine-3-kinase
, which may trigger the degradation of
advanced glycation end-products
(though the true clinical significance of this pathway is unclear). Fructosamine can also refer to the specific compound 1-amino-1-deoxy-D-fructose (
isoglucosamine
), first synthesized by Nobel laureate
Hermann Emil Fischer
in 1886.
[
citation needed
]
Most commonly, fructosamine refers to a laboratory test for
diabetes management
that is rarely used in human clinical practice (simple
blood glucose monitoring
or
hemoglobin A1c
testing are preferred). In small animal veterinary practice however it is part of the diabetic cat or dog diagnosis and monitoring
[1]
giving an indication of blood glucose levels over the previous week.
[2]
Many
direct-to-consumer
lab testing companies sell fructosamine tests.
Use in medicine
[
edit
]
In
diabetes
, maintaining a normal
blood glucose
is essential to preventing many medical complications, including
heart attacks
,
diabetic nephropathy
,
diabetic neuropathy
, and
diabetic retinopathy
eventually leading to
blindness
. Most commonly, blood sugars are measured by either
blood glucose monitoring
which measures the current blood glucose level, or by
glycated hemoglobin
(HbA1c) which measures average glucose levels over approximately 3 months. In a similar way to hemoglobin A1c testing (which measures the
glycation
of hemoglobin), fructosamine testing determines the fraction of total
serum
proteins that have undergone glycation (the
glycated serum proteins
). Since albumin is the most abundant protein in blood, fructosamine levels typically reflect albumin glycation. (Some fructosamine tests specifically quantify the glycation of albumin, or
glycated serum albumin
instead of all proteins.). Because albumin has a
half-life
of approximately 20 days, the plasma fructosamine concentration reflects relatively recent (1?2 week) changes in blood glucose.
[
citation needed
]
In patients with diseases that reduce red blood cell lifespan, such as
hemolytic anaemia
or
hemoglobinopathies
such as
sickle-cell disease
, a hemoglobin-based A1c test can be misleadingly low. A1c results may also be falsely high or low in
hemoglobinopathies
because abnormal hemoglobin variants can interfere in the analysis. In these cases, fructosamine measurement can be used as a marker of
blood sugar
levels, as its measurements are based on albumin instead of hemoglobin. However, any condition that changes serum albumin (such as the
nephrotic syndrome
) will affect the fructosamine result.
[
citation needed
]
In practice, fructosamine is rarely measured clinically (even in individuals with hemoglobinopathies or other red cell disorders) due to a number of pragmatic concerns. First, diabetes care is rarely changed in short (1?4 week) intervals, since diabetes medications can take months to reach a
steady state
. An exception to this is pregnancy, where medication needs can change more rapidly and fructosamine may help provide closer short-term monitoring. Second, fructosamine has higher variability than A1c tests. Third, the overwhelming majority of studies in diabetes care are based on A1c measurements, which can make fructosamine results difficult to interpret. Fourth, the A1c test is very well standardized
[3]
and trusted due to its nearly universal use. A variety of more advanced forms of the A1c test (e.g. some types of
HPLC
,
immunoassay
, and
capillary electrophoresis
) can more accurately assay A1c levels during complex hemoglobinopathies and other conditions.
[4]
However this does not overcome the effect of shortened red blood cell lifespan on A1c results.
[
citation needed
]
In end-stage renal disease (ESRD)
[
edit
]
Because glycated albumin (GA) has a shorter half-life than glycated hemoglobin (HbA1c), glycated albumin reflects recent glycemic control more accurately and usefully for monitoring patients with diabetic
end-stage renal disease
(ESRD) (
hemodialysis
and
peritoneal dialysis
patients). It can be used less often than blood sugar testing. An average blood glucose level of 155?160 mg/dL could be matched to a GA value of 18?19% in patients with ESRD. The ratio of GA/HbA1c is 3.0 approximately.
[5]
Interpretation of results
[
edit
]
There is no standard reference range available for this test. The reference values depend upon the factors of patient age, gender, sample population, and test method. Hence, each laboratory report will include the patient's specific reference range for the test. An increase in fructosamine in lab testing results usually means an increase in glucose in the blood.
On average, each change of 3.3 mmol (60 mg/dL) in average blood sugar levels will give rise to changes of 2% HbA1c and 75 μmol fructosamine values.
[6]
However, this overemphasizes the upper limit of many laboratories' reference ranges of 285 μmol/L as equivalent to HbA1c 7.5% rather than 6.5%. A comparative study,
[7]
which has been used in official advice for
Quality and Outcomes Framework
guidance in the UK
[8]
and summarized by the United States'
National Quality Measures Clearinghouse
,
[9]
gives the following formula and resulting values:
![{\displaystyle {\rm {HbA1c}}={\rm {0.017}}\times {\rm {Fructosamine}}+{\rm {1.61}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/6cf4c986a771d608b837e5510cb17f9378648edd)
- Hence:
![{\displaystyle {\rm {Fructosamine}}=({\rm {HbA1c}}-1.61)\times {\rm {58.82}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/2302725684823693f9d4863213554ff4de98e675)
Fructosamine
(μmol)
|
HbA1c
%
|
HbA1c IFCC
(mmol/mol)
|
200
|
5
|
31
|
258
|
6
|
42
|
288
|
6.5
|
48
|
317
|
7
|
53
|
346
|
7.5
|
58
|
375
|
8
|
64
|
435
|
9
|
75
|
494
|
10
|
86
|
552
|
11
|
97
|
611
|
12
|
108
|
See also
[
edit
]
- ^
Rucinsky R, Cook A, Haley S, Nelson R, Zoran DL, Poundstone M (2010). "AAHA diabetes management guidelines".
J Am Anim Hosp Assoc
.
46
(3): 215?24.
doi
:
10.5326/0460215
.
PMID
20439947
.
- ^
Link KR, Rand JS (December 2008).
"Changes in blood glucose concentration are associated with relatively rapid changes in circulating fructosamine concentrations in cats"
.
J. Feline Med. Surg
.
10
(6): 583?92.
doi
:
10.1016/j.jfms.2008.08.005
.
PMID
18990597
.
S2CID
206050787
.
- ^
National Glycohemoglobin Standardization Program,
https://ngsp.org/
- ^
Sacks, D. B. (2003).
"Hemoglobin variants and hemoglobin A1c analysis: Problem solved?"
.
Clinical Chemistry
.
49
(8): 1245?1247.
doi
:
10.1373/49.8.1245
.
PMID
12881436
.
- ^
Courtesy of Yonsei University College of Medicine (
Yonsei Medical Journal
) (2012).
"Estimating Average Glucose Levels from Glycated Albumin in Patients with End-Stage Renal Disease"
.
Yonsei Med. J
.
53
(3): 578?86.
doi
:
10.3349/ymj.2012.53.3.578
.
PMC
3343437
.
PMID
22477003
.
- ^
Bartol T (2000-12-01).
"Comparison of Blood Glucose, HbA1c, and Fructosamine"
. Retrieved
2007-06-04
.
? gives a comparison chart and cites following source:
- ^
Cohen RM, Holmes YR, Chenier TC, Joiner CH (2003).
"Discordance between HbA1c and fructosamine: evidence for a glycosylation gap and its relation to diabetic nephropathy"
.
Diabetes Care
.
26
(1): 163?7.
doi
:
10.2337/diacare.26.1.163
.
PMID
12502674
.
- ^
"Diabetes (DM) Indicator 20 The percentage of patients with diabetes in whom the last HbA1c is 7.5 or less (or equivalent test/reference range depending on local laboratory) in the previous 15 months"
(PDF)
.
Quality and outcomes framework Guidance 2006
. BMA. p. 39
. Retrieved
2008-01-02
.
- ^
"Diabetes mellitus: the percentage of patients with diabetes in whom the last HbA1c is 7.5 or less (or equivalent test/reference range depending on local laboratory) in the previous 15 months"
. National Quality Measures Clearinghouse. 2007-12-31. Archived from
the original
on 2008-03-10
. Retrieved
2008-01-02
.
External links
[
edit
]