C Mean (SD). d Two patients .... 3. Dunn, M. S., and Drell, W., Experiments .... deed. To establish such a connection beyond doubt requires carefully con-.
Table 1 Relative Changesin SerumPrealbumin,Transferrin,and Albumin in Serumof 16 Patientsbefore and after Implementationof TPN a .
Reference range
PA
200-400
TF ALB
2.0-4.0 gIL 35-50 gIL
a
After
Before
38 (29)%
mg/L
F t#{149}st
66 (35)%
C
46 (16)%
50 (22)% 79 (17)%
70 (15)%
d
First results for the three proteins after two to four weeks of TPN. because they received albumin intravenously.
b
shorter
half-life
markers
dilutions,
=
6.0
p < 0.025
=
0.3 2.3
N.S. N.S.
=
of reference mid-range. All three proteins measured in the same blood
Results shown are percentages
sample. excluded
F F F
such as trans-
C
(SD). d Two patients
Mean
References I. Butterworth, C. E., and Blackburn, G. L., Hospital malnutrition. Nutr. Today 10, 8-18
liminary
(1975).
on
serum
(PA) concentrations patients
before
prealbumin
in undernourished
and during
2. Bistrian,
the course
of
parenteral nutrition. These results indicate the potential usefulness of prealbumin in monitoring TPN. Table 1 compares results observed in 16 patients before and after implementation
TPN.
of continuous
protocol
included
The standard
35 to 50 kilocalories/
kg of body weight per day, mostly in the form ofglucose, amino acids (1.5 to 1.8 g/kg per day), and multivitamins. Albumin (ALB) was measured by a
bromcresol rin (TF)
B. R., Blackburn, G. L., Hollowell, E., et al., Protein status of general surgical patients. J. Am. Med. Assoc. 230, 858-860 (1974). 3. Shetty, P. S., Watrasiewicz, K. E., Jung, R. T., et al., Rapid-turnover transport proteins: An index ofsubclinical protein-energy malnutrition. Lancet ii, 230-232 (1979). 4. Ingenbleek, Y., Vandenschrieck, H. G., Denayer, P., et al., Albumin, transferrin and the thyroxine-binding prealbumin/retinolbinding protein (TBPA-RBP) complex in assessment of malnutrition. Clin. Chim. Acta 63, 61-67 (1975).
green method and transferby nephelometry.
The
Pierre
refer-
with use of specific Tago Inc., Burlingame,
CA. The reference range indicated here for PA was established from data on 40 healthy hospital staff members (20 men and 20 women, ages 20-GO years, mean age 39).
The results depletion
before
indicate
of all three
TPN,
greatest.
These
consistent
that
a pronounced protein
markers
for PA being
preliminary
with and extend
data
Roch
Lapointe
Luc Belanger Services de Biochim. Med. et Chir. Gen. L’H#{244}tel-Dieu de Qu#{233}bec 11 C#{244}teduPalais Qu#{233}bec, Canada, G1R 2J6 1 Address correspondence at the Service de Biochimie
to this author, Medicale.
the are
previous
observations in primary malnutrition (3, 4). The results showed a pronounced depletion of all three protein markers before TPN, but PA showed the greatest
drop. This is consistent
Douville
Jean Talbot’
ence ranges are those currently used in our laboratory. PA was quantitated by electroimmunodiffusion antibody from
with previous
sera
in 0.15 molfL saline, of pooled 1000 blood donors, for which
from
the protein content was estimated by the Kjeldahl method (3) to be 70 gIL. The curve was linear between 44 and 700 mg of protein per liter. If necessary, was diluted in 0.15 mol/L saline.
The
ferrin (eight days) and prealbumin (two days) (3, 4). We report here our predata
per liter just before use. The flow rate is for CSF and 1 mL/min for TCA. The assay was calibrated by use of 0.1 mL/min
total
protein
content
CSF
of 114
samples of CSF was determined with the same standards, either by our method or by the method of Lowry et a!. (4). The
correlation
coefficient
for the
two
methods was 0.989 (y -1.54 + 1.OOx). Two highly discrepant results for the same patient were excluded. As tabulated below, these two pathological samples were characterized by very high
concentrations of IgG, and this could explain the discrepancy; similar concentrations procedure et
estimated by the Kjeldahl give, in the method of Lowry
al., a higher optical
than
for albumin
density
for IgG
(5).
Total protein, gIL NepheloLowry Albumin, IgG, metry method gILO gILa 0.66 1 0.19 0.26 0.36 0.65 0.165 0.14 a As determined by immunonephelornetry ( 7) with the same equipment Within-day precision was evaluated by use of three CSF samples containing 167, 282, and 657 mg of protein per liter, the assay being repeated 20 times on the same day with the same calibration curve. The CV’s were respectively 1.6,
1, and 1.1%. The CV’s for the amongdays comparison, made on three CSF samples with 262, 492, and 595 mg of protein per liter, the assays being re-
peated once during each of 20 days, were
Automated Nephelometry of Total Protein in Cerebrospinal Fluid
respectively 5.3, 3.6, and 5.5%. As outlined by Reiber (6), who used a
Beckman metric
To the Editor:
of
nephelometer,
assay
choice
for
could
become
determination
the nephelothe method of total
Total protein in cerebrospinal fluid (CSF) is commonly determined by tnchloroacetic acid (TCA) precipitation and turbidimetry (1). TCA has an advantage over sulfosalicylic acid in that it gives the same optical density for al-
protein
only marker that showed a rapid and significant increase toward normal values after introduction of TPN. The possibility that TPN per se might induce PA
changes
bumin
nologically with only minor modification of the flow diagram (7).
observations in primary malnutrition 4). Furthermore, PA was the
tion
mote:
(3,
unrelated to nutritional condibe ruled out, but seems rein primary malnutrition, low
cannot
and globulin
centrations
in the same con-
(1).
In our technique consists
for three weeks (4). These data thus suggest that PA may be a more sensitive
lowing modules: immunoprecipitin
marker than albumin or transferrin for the assessment of nutritional status and for monitoring rapid nutritional changes induced by TPN.
ronephelometer, and a linear recorder. The rate of sampling (25 zL) is 120 per hour and the incubation time in the mixing coil 2 mm. The CSF is pumped into the line of a 0.18 mol/L TCA (Merck, Darmstadt, F.R.G.) solution, to which was added 150 L of Tween 20
We thank Andr#{233}e Bilodeau Lajoie for their assistance.
and Nicole
and, after the TCA line is washed, IgG and albumin can be determined immu-
the instrumentation
serum PA concentrations rapidly revert to normal after a balanced diet is given
of a Technicon
NY) AutoAnalyzer
in CSF. In our continuous-flow
system this method is automated, requires only 25 zL of CSF rather than 0.5 to 1 mL as in Meulemans’ technique (1),
(Tarrytown,
including
References
the fol-
Sampler II, Pump III, manifold (2), fluo-
1. Meulemans, 0., Determination of total protein in spinal fluid with suiphosalicylic acid and trichloroacetic acid. Clin. Chim. Acta 5, 757-761 (1960). 2. Cambiaso, C. L., Masson, P. L., Vaerinan, J. P., and Heremans, J. F., Automated nephelometric immunoassay (ANIA). I. Importance of antibody affinity. J. Immunol. Methods 5,153-163(1974). 3. Dunn, M. S., and Drell, W., Experiments
CLINICAL CHEMISTRY,
Vol. 28, No. 7, 1982
1707
in Biochemistry, 1st ed., McGraw-Hill, New York, NY, 1951, p 110. 4. Lowry, 0. H., Rosebrough, N. J., Farr, A.
L., and Randall, R. J., Protein measurement
by AAS:
Bello-Reuss
et al. (8) gave a (n 9) and et al. (9) detected 20 ± 11 8) in serum of workers occu-
value of 400 ± 120 tg/L Kiviluoto tg/L (n
=
with the Folin phenol reagent. J. Biol. Chem. pationally exposed to V at the start of 193, 265-275 (1951). their holiday and 13 ± 4 zgIL in the 5. Laterre, E. C., Lea prot#{233}ines du liquide same individuals at the end of their c#{233}phalo-rachidiend l’#{233}tat normal et pat hoholiday (between seven and 29 days). logique, Arscia, Bruxelles, 1965. The V content of human urine re6. Reiber, H., Eine schnelle und einfache portedly is of the same order of magninephelometrisehe Bestimmungsmethode f#{252}r tude as that in serum. Stroop et al. (1) Protein im Liquor cerebrospinalis. J. Clin. found 4.0 to 12 gIL (n = 4) and KiviChem. Biochem. 18, 123-127 (1980). luoto et al. (9) about 19 ± 10 sgIL for 7. Britain, C. E., Butts, J. D., and Killingnon-exposed individuals (recalculated sworth, L. M., CSF/serum.specific ratios in values, assuming 2.0 g of creatinine per the diagnosis of neurological disease. In Ad1.5 L urine a day). These values are vances in Automated Analysis. Tech nicon International Congress 1976, 1, Mediad, Inc., much higher than the upper limit of Tarrytown, NY, 1977, pp 274-277.
