Use of the hand refractometer in determining total serum proteins of infants and children

Thoene, Jess G.; Talbert, James L.; Subramanian, Sandya; Odell, Gerard B.

doi:10.1016/s0022-3476(67)80304-4

Cited by 12 publications

(5 citation statements)

References 5 publications

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“…Although results from refractometry and biuret techniques correlate well for human serum samples, 4,10–12,21 correlation for veterinary samples is less consistent. Numerous authors reported good correlation during the 1960s, 1970s and early 1980s.…”

Section: Protein Measurement By Refractometrymentioning

confidence: 85%

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The Usefulness and Limitations of Hand‐held Refractometers in Veterinary Laboratory Medicine: An Historical and Technical Review

George¹

2001

Veterinary Clinical Pathol

137

132

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Medical hand-held refractometers have been used in veterinary practice since their development in the 1960s. They have become ubiquitous for the measurement of protein and urine solute concentrations because of their rapidity of analysis, ease of use, and relatively low cost. Refraction of light offers advantages for the determination of solute concentrations because the measurement requires no chemical alteration of the specimen. Numerous authors have reported that the results of protein estimation by refractometry for domestic mammals correlate well with those obtained by the biuret method, although others have reported both higher and lower refractometric results compared with biuret results. Major discrepancies between biuret and refractometric results have been reported for avian samples. Some of the variation in reported results may be due to differences in design by refractometer manufacturers. Another possible source may be variation in the biuret reagent mixture and assay conditions. Refractometers also can be used to calculate serum water concentration. A table that converts index of refraction to serum water concentration can be used to convert electrolyte concentration from mmol/L of serum to mmol/L of serum water, a more accurate indicator of effective electrolyte concentration. Refractometers are especially useful for determining urine specific gravity on veterinary samples because they require relatively small sample volumes. Specific gravity continues to be the most common unit for reporting total solids concentration. Some solutes, such as acetone, may cause false increases in specific gravity by refractometry, as they increase refraction but are less dense than water.

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Section: Protein Measurement By Refractometrymentioning

confidence: 85%

“…However, the requirement for constant temperature during measurement still limited its usefulness in clinical settings. When hand‐held temperature‐compensated medical refractometers were introduced in the 1960's, refractometry became the standard technique for rapid protein determination 10–12 …”

Section: Protein Measurement By Refractometrymentioning

confidence: 99%

The Usefulness and Limitations of Hand‐held Refractometers in Veterinary Laboratory Medicine: An Historical and Technical Review

George¹

2001

Veterinary Clinical Pathol

137

132

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“…Correlations between refractometric and Biuret TP determinations are good on human fluid samples,7–9 11 12 and mildly lower in animal samples 13–18. In this study, differences between Biuret and refractometric method of total protein determination were found only for samples containing high concentrations of K 2 EDTA and not for LH, which suggests that the anticoagulant used may have caused the main difference in the refractometric determination of TP.…”

Section: Discussionmentioning

confidence: 51%

“…Refractometric determination of total protein in biological fluids including SF is widely used in equine practice. Overall, good correlation between refractometry and Biuret techniques has been reported when determining TP on human serum [7][8][9][10][11][12] ; however, results have been less consistent for animal serum or plasma. [13][14][15][16][17][18] Total protein determination by refractometry is based on the angle of refraction of light, which is produced by the combined concentration of all its solutes or 'total solids'.…”

Section: Discussionmentioning

confidence: 99%

Concentration of dipotassium ethylenediaminetetraacetic acid but not lithium heparin affects total protein determination in equine synovial fluid

Rihuete¹,

Villarino

Pelisiak

et al. 2020

Veterinary Record

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BackgroundRefractometric determination of total protein (TP) in synovial fluid (SF) is commonly used for diagnosis and monitoring of synovial sepsis in horses. Previous studies have shown that elevated concentrations of certain anticoagulants may overestimate refractometric determination of TP concentration.ObjectivesThe aim of the study was to evaluate the effect of different concentrations of dipotassium EDTA (K2EDTA) and lithium heparin (LH) on TP determination by using a hand-held refractometer in equine synovial fluid.Study designCross-section observational study.MethodsThirty samples of synovial fluid obtained from 22 horses with different synovial conditions were collected. Synovial fluid samples were separated into different aliquots and placed in commercially available collection tubes containing K2EDTA or LH at four different concentrations (1.76, 3.52, 7.04 and 17.6 mg/ml for K2EDTA; 16, 32, 64 and 160 IU/ml for LH) . Refractometric TP determination was performed on untreated and K2EDTA and LH aliquots with a hand-held refractometer and by spectophotometric Biuret method as the gold standard.ResultsRefractometric TP determination was overestimated in SF samples containing 10 times the recommended K2EDTA concentrations. Lower concentrations of K2EDTA and LH concentrations did not affect refractometric TP determinations.Main limitationsLimited number of samples mostly obtained from large synovial structures.ConclusionTo avoid incorrect TP determination, the use of LH containing collection tubes may be an appropriate alternative when the SF volume available is not enough to fill the K2EDTA collection tube.

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“…The latter is influenced by fibrinogen levels and other plasma proteins [23,24]. We studied total blood solutes, which were reported to have a high correla tion with-plasma proteins [25], There was no correlation between total blood solutes and venous Hct at birth or later.…”

Section: Discussionmentioning

confidence: 98%

Polycythemia of the Preterm and Full-Term Newborn Infant: Relationship between Hematocrit and Gestational Age, Total Blood Solutes, Reticulocyte Count, and Blood pH

Carmi

Wolach²,

Dolfin³

et al. 1992

Neonatology

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The umbilical venous hematocrit at birth (Hct 1) and the peripheral venous hematocrit at 2 h of life (Hct 2) were determined in 78 healthy full-term and 14 healthy preterm newborn infants. Hct 1 was 51.6 ± 4.1 % in full-term infants and 50.8 ± 4% in preterm infants. Hct 2 was 60.9 ± 2 and 58.6 ± 6.1% in full-term and preterm infants, respectively. Significant differences between Hct 1 and Hct 2 were found in both groups of infants (p < 0.01). The blood viscosity increased significantly in both groups from birth to 2 h of life. Neonatal polycythemia (Hct higher than 70% at 2 h of life) was detected in only 3 full-term infants (3.8%). They received partial exchange transfusion. There was a positive linear correlation of Hct 1 with Hct 2 in full-term newborns (r = 0.71 p < 0.001) and preterm infants (r = 0.57, p < 0.02). No infants with Hct 1 equal to or below 50% had Hct 2 higher than 65%. None with Hct 1 between 51 and 54% had Hct 2 higher than 70%. Neither Hct 1 nor Hct 2 correlated with birth weight, gestational age, total blood solutes, or reticulocyte counts at birth in either group. An inverse linear correlation was found between blood pH at birth and Hct 2 in preterm newborn infants (r = 0.66, p < 0.02).

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Use of the hand refractometer in determining total serum proteins of infants and children

Cited by 12 publications

References 5 publications

The Usefulness and Limitations of Hand‐held Refractometers in Veterinary Laboratory Medicine: An Historical and Technical Review

The Usefulness and Limitations of Hand‐held Refractometers in Veterinary Laboratory Medicine: An Historical and Technical Review

Concentration of dipotassium ethylenediaminetetraacetic acid but not lithium heparin affects total protein determination in equine synovial fluid

Polycythemia of the Preterm and Full-Term Newborn Infant: Relationship between Hematocrit and Gestational Age, Total Blood Solutes, Reticulocyte Count, and Blood pH

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