TABLE 17-1
P roperties o f S eru m /P lasm a B io ch em ica l M arkers U sed in th e A ssessm en t o f P rotein E n ergy M aln u trition
Biochemical Marker
Site of Synthesis
and Molecular
in the
Concentration during
Normal(N), Mild, Moderate,
and Severely Depleted States
Properties and Clinical Utility
M.W.: 66,000
15-19 days
N: 3.5-5.0 g/dl
Mild: 2.8-3.5 g/dl
Moderate: 2.1-2.7 g/dl
Severe: <2.1 g/dl
Transports many endogenous and
exogenous ligands, major determinant of
plasma oncotic pressure. Large body pool
and long half-life makes it a poor index of
acute malnutrition
Transthyretin (also
known as prealbumin)
plasma circulating
form is a tetramer
composed of four
identical monomers.
M.W.: 55,000
1-2 days
N: 20-40 mg/dl
Mild: 10-15 mg/dl
Moderate: 5-10 mg/dl
Severe: <5 mg/dl
Circulates in plasma in a 1:1 complex with
retinol-binding protein, transports
thyroxine, has a small body pool, and has a
short half-life. Sensitive indicator of
protein deficiency and in the improvement
with protein refeeding.
protein (RBP)
M.W.: 21,000
10-12 hours
N: 3.5-9.0 mg/dl
Circulates in plasma in 1:1 complex with
transthyretin, transports retinol and
thyroxine, plasma levels influenced by
glomerular filtration rate, retinol and zinc
status, considered to be too sensitive and
therefore has limited value
M.W.: 77,000
8.8 days
N: 225-400 mg/dl
Mild: 150-200 mg/dl
Moderate: 100-150 mg/dl
Severe: <100 mg/dl
Transports iron in the ferric state; serum
levels rise proportional to iron deficiency,
a better marker than albumin however, not
suitable in the short-term hospital setting.
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