Analytical performance of three commercially available nephelometers compared for quantifying proteins in serum and cerebrospinal fluid.

Salden, H. J. M.; Bas, B. M.; Hermans, I. T. H.; Janson, Paul

doi:10.1093/clinchem/34.8.1594

Cited by 32 publications

(14 citation statements)

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“…Our evaluation revealed within-run and total precision performance that was equivalent or superior to the existing commercial nephelometric and turbidimetric immunoassays (23,24). We found the assays to be linear over the calibration range and the analytical sensitivity consistent with previously described findings for serum proteins (7).…”

Section: Discussionsupporting

confidence: 83%

Development and validation of 14 human serum protein assays on the Roche cobas® c 501

Ledue

Collins

2011

J. Clin. Lab. Anal.

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Many laboratories rely on dedicated nephelometers and turbidimeters for the measurement of serum proteins. There are, however, a number of chemistry analyzers that offer open channel configurations for end-user applications. We developed and validated 14 human serum protein assays (α(1)-antitrypsin, α(2)-macroglobulin, albumin, apolipoproteins AI and B, complement components 3 and 4, haptoglobin, immunoglobulins A, G, and M, orosomucoid, transferrin, and transthyretin) on the Roche cobas(®) c 501. We obtained excellent precision at low, normal, and high physiologic concentrations of each protein (within-run imprecision CVs ≤2.5%, total imprecision CVs ≤3.6%). Linearity for each method was within 5% of the expected value throughout the calibration range, and method comparison studies to commercial assays from Roche or Siemens were in good agreement (r>0.975). We observed no significant interference from bilirubin (up to 414 mg/l), hemoglobin (up to 8.9 g/l), triglyceride (up to 28 g/l), or rheumatoid factor (up to 3,930 IU/ml). Calibration was stable for at least 14 days. The instrument's small reaction cell allowed us to conserve nearly 60% of our specimen and reagent volume compared with our previous system. These newly developed assays provide precise and accurate results with high throughput, but without the associated cost of a dedicated instrument.

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Section: Discussionsupporting

confidence: 83%

Development and validation of 14 human serum protein assays on the Roche cobas® c 501

Ledue

Collins

2011

J. Clin. Lab. Anal.

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“…All analyses were performed on the 2nd-4th ml of CSF after lumbar puncture. For every patient albumin levels were measured as part of the diagnostic work-up in cell-free CSF and paired serum samples by immunochemical nephelometry with the Beckman Array Protein System or IMMAGE 800 Immunochemistry System (Beckman Instruments, Fullerton, CA, USA) according to the procedure of Salden [20]. Albumin quotient was calculated to disclose B-CSF-B dysfunction according to the formula: QAlb = [Alb]CSF/[Alb]serum × 1000.…”

Section: Methodsmentioning

confidence: 99%

Increased age and male sex are independently associated with higher frequency of blood–cerebrospinal fluid barrier dysfunction using the albumin quotient

Castellazzi

Morotti²,

Tamborino

et al. 2020

Fluids Barriers CNS

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Background: The cerebrospinal fluid (CSF)/serum quotient of albumin (QAlb) is the most used biomarker for the evaluation of blood-cerebrospinal fluid barrier (B-CSF-B) permeability. For years QAlb was considered only as an age-related parameter but recently it has also been associated to sex. The aim of the present study was to explore the impact of sex in the determination of B-CSF-B dysfunction. Methods: The analysis was retrospectively conducted on subjects consecutively admitted to the neurological ward. CSF and serum albumin levels were measured by immunonephelometry and pathological QAlb thresholds were considered: 6.5 under 40 years, 8.0 in the age 40-60 and 9.0 over 60 years. Results: 1209 subjects were included in the study. 718 females and 491 males (age: 15-88 years): 24.6% of patients had a diagnosis of multiple sclerosis, 23.2% suffered from other inflammatory neurological diseases, 24.6% were affected by non-inflammatory neurological diseases, and for 27.6% of patients the final neurological diagnosis could not be traced. Dysfunctional B-CSF-B was detected more frequently (44 vs. 20.1%, p < 0.0001) and median QAlb value were higher (7.18 vs. 4.87, p < 0.0001) in males than in females in the overall study population and in all disease subgroups. QAlb and age were positively correlated both in female (p < 0.0001) and male (p < 0.0001) patients, however the slopes of the two regression lines were not significantly different (p = 0.7149), while the difference between the elevations was extremely significant (p < 0.0001) with a gap of 2.2 units between the two sexes. Finally, in a multivariable linear regression analysis increased age and male sex were independently associated with higher QAlb in the overall study population (both p < 0.001) and after stratification by age and disease group. Conclusions: Accordingly, identification and validation of sex-targeted QAlb thresholds should be considered as a novel tool in an effort to achieve more precision in the medical approach.

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“…CSF and serum IgG levels were measured by immunochemical nephelometry with the Beckman Immage 800 Immunochemistry System (Beckman Instruments, Inc. Fullerton, CA. USA) according to the procedure of Salden et al [ 56 ].…”

Section: Methodsmentioning

confidence: 99%

Comparison of Antibodies with Amylase Activity from Cerebrospinal Fluid and Serum of Patients with Multiple Sclerosis

et al. 2016

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We have recently shown that IgGs from serum and cerebrospinal fluid (CSF) of MS patients are active in hydrolysis of DNA and myelin basic protein. According to literature data, anti-DNA and anti-MBP abzymes may promote important neuropathologic mechanisms in this chronic inflammatory disorder and in MS pathogenesis development. At the same time, the involvement of antibodies with amylase activity in the pathogenesis of any autoimmune disease has not yet been identified. Electrophoretically and immunologically homogeneous IgGs were obtained by a sequential affinity chromatography of the CSF proteins on protein G-Sepharose and FPLC gel filtration. We are able to present the first unpredictable evidence showing that IgGs from CSF possess amylase activity and efficiently hydrolyze maltoheptaose; their average specific Ab activity is ~30-fold higher than that of antibodies from sera of the same MS patients. Specific average RA (SAA) for IgGs from healthy volunteers was approximately ~1000 lower than that for MS patients. In addition, it was shown that a relative SAA of total proteins of CSF (including Abs) ~15-fold lower than that for purified IgGs, while the relative SAA of the total sera protein is higher than that of sera IgGs by a factor of 1033. This result speaks in favor of the fact that amylolytic activity of CSF proteins is mainly caused by the activity of amylase abzymes. One cannot exclude, that amylase abzymes of CSF can play a, as yet unknown, role in the pathogenesis of MS. Some possible reasons of these findings are discussed.

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Analytical performance of three commercially available nephelometers compared for quantifying proteins in serum and cerebrospinal fluid.

Cited by 32 publications

References 0 publications

Development and validation of 14 human serum protein assays on the Roche cobas® c 501

Development and validation of 14 human serum protein assays on the Roche cobas® c 501

Increased age and male sex are independently associated with higher frequency of blood–cerebrospinal fluid barrier dysfunction using the albumin quotient

Comparison of Antibodies with Amylase Activity from Cerebrospinal Fluid and Serum of Patients with Multiple Sclerosis

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