scholarly journals A WHO Reference Reagent for lupus (anti-dsDNA) antibodies: international collaborative study to evaluate a candidate preparation

2019 ◽  
Vol 78 (12) ◽  
pp. 1677-1680 ◽  
Author(s):  
Bernard J Fox ◽  
Jason Hockley ◽  
Peter Rigsby ◽  
Carl Dolman ◽  
Pier Luigi Meroni ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Collaborative Study ◽  
Test Methods ◽  
Common Reference ◽  
Double Stranded Dna ◽  
Reference Preparation ◽  
International Collaborative ◽  
And Control ◽  
Dsdna Antibodies ◽  
International Collaborative Study

IntroductionAntibodies against double-stranded DNA (anti-dsDNA) are a specific biomarker for systemic lupus erythematosus (SLE). The first WHO International Standard (IS) for anti-dsDNA (established in 1985), which was used to assign units to diagnostic tests, was exhausted over a decade ago.MethodsPlasma from a patient with SLE was first evaluated in 42 European laboratories. The plasma was thereafter used by the National Institute for Biological Standards and Control to prepare a candidate WHO reference preparation for lupus (anti-dsDNA) antibodies. That preparation, coded 15/174, was subjected to an international collaborative study, including 36 laboratories from 17 countries.ResultsThe plasma mainly contained anti-dsDNA, other anti-chromatin antibodies and anti-Ku. The international collaborative study showed that the field would benefit from 15/174 as a common reference reagent improving differences in performance between different assays. However, no statistically meaningful overall potency or assay parallelism and commutability could be shown.Conclusion15/174 cannot be considered equivalent to the first IS for anti-dsDNA (Wo/80) and was established as a WHO Reference Reagent for lupus (oligo-specific) anti-dsDNA antibodies with a nominal value of 100 units/ampoule. This preparation is intended to be used to align test methods quantifying levels of anti-dsDNA antibodies.

International Collaborative Study for the Calibration of a Proposed Reference Preparation for Thromboplastin, Human Recombinant, Plain

1998 ◽  
Vol 79 (02) ◽  
pp. 439-443 ◽  
Author(s):  
Veena Chantarangkul ◽  
Barbara Negri ◽  
Marigrazia Clerici ◽  
Pier Mannuccio Mannucci ◽  
Armando Tripodi
Keyword(s):  
Collaborative Study ◽  
Mean Value ◽  
World Health ◽  
Practical Reasons ◽  
Calibration Model ◽  
Average Value ◽  
Reference Preparation ◽  
International Collaborative ◽  
Health Organization ◽  
International Collaborative Study

SummaryStocks of the International Reference Preparation (IRP) for thromboplastin, human, plain, coded BCT/253 and held by the World Health Organization (WHO) are nearly exhausted and must be replaced. For practical reasons the choice of the replacement candidate was restricted to two available human recombinant preparations which were coded as X/95 and Y/95 and calibrated in an international collaborative study involving 19 laboratories from Europe, Australia, Canada and Argentina. To minimize the differences between routes of calibration, the two candidates were calibrated against the existing WHO-IRP from human, rabbit and bovine origin and the final ISI was the resultant average value. On the basis of predefined criteria (i.e., within- and between-laboratory precision of the calibration and the conformity to the calibration model), X/95 was the preferred candidate. The assigned ISI (SE of the mean) value is 0.940 (0.0060) and the interlaboratory coefficient of variation 4.7%.

The Second International Reference Preparation of Thyroid-Stimulating Hormone, Human, for Immunoassay: calibration by bioassay and immunoassay in an international collaborative study

1985 ◽  
Vol 104 (3) ◽  
pp. 367-379 ◽  
Author(s):  
R. E. Gaines Das ◽  
A. F. Bristow
Keyword(s):  
Collaborative Study ◽  
Thyroid Stimulating Hormone ◽  
World Health ◽  
Expert Committee ◽  
International Reference ◽  
Reference Preparation ◽  
International Collaborative ◽  
Health Organization ◽  
International Collaborative Study ◽  
Second International

ABSTRACT Four batches of ampouled materials in ampoules coded 80/558, 81/502, 81/565 and 81/615 were evaluated by 22 laboratories in nine countries in an international collaborative study for their suitability to serve as a replacement for the First International Reference Preparation (IRP) of TSH, Human, for Immunoassay. The ampouled preparations were calibrated by immunoassay and bioassay. The preparation coded 80/558 had satisfactory stability and contained acceptably low levels of contamination with FSH and LH. Estimates of the immunoreactive TSH content of a set of specimens of serum in terms of 80/558 showed agreement in ranking order and no increase in variability compared with estimates made by assay against the First IRP. On the basis of these results, with the agreement of the participants in the study, and with the authorization of the Expert Committee on Biological Standardization of the World Health Organization, the preparation coded 80/558 was established in 1983 as the Second International Reference Preparation of TSH, Human, for Immunoassay, with a defined potency of 37 mi.u./ampoule. Preparations coded 81/502, 81/565 and 81/615 were found suitable to serve as working standards. J. Endocr. (1985) 104, 367–379

International Collaborative Study for the Establishment of the Second International Reference Preparation of Plasmin

1983 ◽  
Vol 50 (03) ◽  
pp. 645-649 ◽  
Author(s):  
P J Gaffney ◽  
M V Mussett
Keyword(s):  
Collaborative Study ◽  
World Health ◽  
Expert Committee ◽  
Glycerol Solution ◽  
International Reference ◽  
Freeze Dried ◽  
Reference Preparation ◽  
International Collaborative ◽  
International Collaborative Study ◽  
Second International

SummaryAn international collaborative study involving seven laboratories was undertaken to assess the suitability of a freeze- dried preparation of human plasmin to replace the current International Reference Preparation (IRP) for plasmin. Chromogenic and fibrinolytic assays were used by all participating laboratories to assess the potencies of the Proposed International Reference Preparation (PIRP) and two other freeze-dried plasmins, one of human and one of porcine originThe data suggest that the PIRP is a more suitable standard for plasmin than the IRP in that the former binds to fibrin whereas only 50% of the latter binds. The PIRP compared well to other plasmin preparations and the potency assays were independent of the assay procedure and substrate used. Degradation studies indicated that the PIRP was far more stable than the glycerol solution of the IRP, surviving for 12 months at 37° C with no significant loss in either amidolytic or fibrinolytic activity. The International Committee for Thrombosis and Haemostasis (Bergamo, 1982) has recommended the use of this material as a standard and it has been established by the Expert Committee on Biological Standardization of the World Health Organization as the second International Reference Preparation for Plasmin with a defined potency of 10 International Units of Plasmin per ampoule.

International Collaborative Study on the Assay of Commercially Available High and Low Molecular Weight Urokinases

1981 ◽  
Vol 45 (01) ◽  
pp. 034-037 ◽  
Author(s):  
P J Gaffney ◽  
S M Tydeman ◽  
T B L Kirkwood ◽  
D Aronson ◽  
G Murano
Keyword(s):  
Molecular Weight ◽  
Collaborative Study ◽  
Relative Potency ◽  
Low Molecular Weight ◽  
International Reference ◽  
Molecular Weights ◽  
Reference Preparation ◽  
International Collaborative ◽  
International Collaborative Study

SummaryUrokinases of different molecular weights are now commercially available. An international collaborative study (eight laboratories) has been conducted to investigate the effect of type and concentration of plasminogen on the assay of two different urokinase preparations against the International Reference Preparation (IRP). Considerable inter-laboratory variation in relative potency estimation was found, and a small effect of plasminogen concentration, independent of type, was apparent.

An International Collaborative Study of 69/104, a Reference Preparation of Human Pituitary FSH and LH

1973 ◽  
Vol 36 (4) ◽  
pp. 647-660 ◽  
Author(s):  
D. R. BANGHAM ◽  
I. BERRYMAN ◽  
H. BURGER ◽  
P. MARY COTES ◽  
BRIDGET E. FURNIVAL ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Human Pituitary ◽  
Reference Preparation ◽  
International Collaborative ◽  
International Collaborative Study

An international collaborative study on standardization of apolipoproteins A-I and B. Part I. Evaluation of a lyophilized candidate reference and calibration material.

1987 ◽  
Vol 33 (12) ◽  
pp. 2240-2249 ◽  
Author(s):  
S J Smith ◽  
G R Cooper ◽  
L O Henderson ◽  
W H Hannon
Keyword(s):  
Reference Material ◽  
Collaborative Study ◽  
Study Data ◽  
World Health ◽  
Expert Committee ◽  
Response Curves ◽  
Apo B ◽  
Reference Preparation ◽  
International Collaborative ◽  
International Collaborative Study

Abstract We evaluated a lyophilized serum preparation for use as a candidate Reference Material for apolipoproteins (apo) A-I and B. An international collaborative study was conducted with 28 participating laboratories, selected on the basis of participation and demonstrated expertise in a 1983 survey of apolipoproteins A-I and B. The analytical suitability of the material was established by confirming linearity of its dose-response curves over a desired concentration range and demonstrating that its response curves paralleled those for fresh sera. Differences in dilution-adjusted mass units ascribable to the five analytical methods used by the various laboratories constituted only 1% of the total variation for apo A-I, but 32% for apo B. The dominant source of error, however, for both apo A-I and B was the variability among laboratories, rather than variability among methods and antisera. The assigned consensus mass-concentration units based on study data are 1.124 g/L for apo A-I, 0.589 g/L for apo B. For these estimates the coefficients of variation were 13% and 27%, respectively. These findings on the proposed Reference Material meet the requirements suggested by the World Health Organization's Expert Committee on Biological Standards for a candidate WHO Reference Preparation.

An International Collaborative Study Establishing a Reference Preparation for Antithrombin III

1980 ◽  
Vol 43 (01) ◽  
pp. 010-015 ◽  
Author(s):  
T B L Kirkwood ◽  
T W Barroweliffe ◽  
D P Thomas
Keyword(s):  
Antithrombin Iii ◽  
Collaborative Study ◽  
World Health ◽  
Normal Plasma ◽  
Freeze Dried ◽  
At Iii ◽  
Reference Preparation ◽  
International Collaborative ◽  
Suitable Reference ◽  
International Collaborative Study

SummaryAn international collaborative study involving 12 laboratories in 7 countries was carried out to establish a suitable reference preparation of antithrombin III (At III). The amount of At III present in two purified preparations, a freeze-dried normal plasma and local normal plasma pools was measured by clotting, immunological, and amidolytic assays. 120 assays were submitted of which 105 were accepted as valid for inclusion in subsequent analyses. Less laboratory to laboratory variation was found when At III was assayed in freeze-dried normal plasma, as compared to purified preparations of At III, and there was also less method to method variation when At III was measured in freeze-dried plasma. When measured as heparin co-factor activity, the two purified preparations contained only about half the level of At III found by immunoassay or progressive At III clotting assays. In contrast, the use of freeze-dried plasma provided results which showed excellent agreement between the various laboratories by all assays; accordingly, this material has been established by the World Health Organization as the International Reference Preparation for At III, with an assigned potency of 0.9 i. u. per ml.

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