Table 1. RelativeChangesinSerumPrealbumin ... - Clinical Chemistry

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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.

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