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The complement components C3 and C4 are part of the complement system. The complement system has many tasks to perform in the body and consists of several proteins that all have unique tasks. C3 and C4 are examined, for example, if a deficiency is suspected, in the presence of autoimmune diseases or in the case of recurring bacterial infections. When verifying the analysis and after analyzing of external controls, it has been shown that the reference range is falsely high, especially for C3. The study therefore aimed to verify the analysis of C3 and C4 on Atellica NEPH 630 and establish a correct reference range for respective analysis. The method was verified by evaluating the precision of the method and by comparing the concentration of C3 and C4 measured on Cobas 6000 module C500 with the concentration measured on Atellica NEP 630. In addition, the reference intervals provided by Siemens were evaluated using samples from blood donors and from other healthy individuals. The verification began by performing quality controls on three different levels before analysis of samples. The coefficient of variation was less than 5 % for all control levels for both complement analysis. Reference values ​​for C3 were not in alliance with the reference values ​​provided by Siemens. A new proposed range for C3 is 0.48- 1.37 g/L, while the recommended range can be used for C4.

En förhöjd produktion av fria kappakedjor (KFLC) i serum observeras vanligen vid inflammatoriska processer och vid autoimmuna sjukdomar. En överproduktion av fri kappakedja utgör en markör för intratekal immunglobulinproduktion i centrala nervsystemet (CNS) vilket kan ofta ses vid multipel skleros och andra inflammatoriska nervsjukdomar. Detta kan mätas både kvantitativt genom IgG index med nefelometri och kvalitativt genom att påvisa oligoklonala band i cerebrospinalvätska (CSV) med isoelektrisk fokusering. Syftet med studien är att sätta upp analys för bestämning av fri kappa-kedja i likvor på en nefelometer och utvärdera olika kvantitativa mått för intratekal Ig-syntes där fri kappakedja ingår genom att jämföra de mot isoelektrisk fokusering, vilket är dagens standardmetod för att påvisa intratekal Ig syntes. Studien erhöll goda resultat för olika KFLC parametrar jämfört med oligoklonalaband, där KFLC IF påvisade högst sensitivitet och specificitet (72% och 93%) jämfört med oligoklonala band., An increased production of free coat chains in (KFLC) serum is commonly observed in inflammatory processes and in autoimmune diseases. An overproduction of free kappa chain is a marker for intrathecal immunoglobulinproduction in the central nervous system (CNS), which can often be seen in multiple sclerosis and other inflammatory nerve diseases. This can be measured both quantitatively by IgG index with nephelometry and qualitatively by detecting oligoclonal bands in cerebrospinal fluid (CSF) with isoelectric focusing. The purpose of the studies is to set up analysis for determination of free kappa chain in liquids on a nephelometer and evaluate different quantitative measures for intrathecal Ig synthesis where free kappa chain is included by comparing them against isoelectric focusing, which is the current standard method for detecting intrathecal Ig synthesis. The study obtained good results for different KFLC parameters compared to oligoclonal bands, where KFLC IF has the highest sensitivity and specificity (72%and 93%) compared to oligoclonal bands.

Background: The study of hematic concentrations of alpha1 antitrypsin (AAT) is currently one step in the diagnosis of AAT deficiency. To try to clarify the relevance of the laboratory techniques, we carried out a systematic review of the literature. Methods: Studies evaluating the quantification of AAT in peripheral blood were searched in PubMed in July 2021. The selection criteria included (1) any type of study design that included a quantification of AAT in peripheral blood; (2) studies written in English or Spanish; (3) studies evaluating human beings; and (4) studies involving adults. Results: Out of 207 studies, the most frequently used techniques were nephelometry (43.9%), followed by ELISA (19.8%) and turbidimetry (13.5%). Altogether, 182 (87.9%) cases expressed their results in units of gram, while 16 (7.7%) articles expressed them in units of mole. Only 2.9% articles referred to the standard used, 43.5% articles indicated the commercial kit used, and 36.2% indicated the analyzer used. Conclusions: The technical aspects of these determinations are not always reported in the literature. Journals should be attentive to these technical requirements and ensure that they are included in the works in which AAT is determined in order to ensure a correct interpretation of the study findings.

Levels of Immunoglobulin G (IgG)-subclasses are analyzed when patients have reoccurring infections and in order to follow the treatment of IgG4 related disease. The measured quantity of IgG-total can be within the reference interval even if the patient has a deficiency in one of the IgG-subclasses. Due to this Sundsvall’s hospital plans to begin analyzing IgG-subclasses. The aim was to verify the performance level of the analysis IgG-subclasses (IgG1-4) with Siemens Atellica NEPH 630. The method was verified by evaluating the method’s precision and by comparing the sum of IgG-subclasses with the quantity of IgG-total analyzed on Cobas c502. In addition, the reference intervals provided by Siemens were evaluated using samples from blood donors. The study evaluated whether there was a correlation between infection with SARS-CoV2 and a deficiency in IgG-subclasses. The verification began by performing quality control twice daily over a period of four weeks. The IgG-subclasses test was performed on blood donor samples with Siemens Atellica NEPH 630 for evaluation of the reference values. The coefficient of variation was less than 6 % for all four subclasses. The reference values for IgG1, IgG2, IgG3, and IgG4 are all in alliance with the reference values provided by Siemens. The sum of IgG-subclasses corresponded well with IgG-total with a correlation value (R) 0.82. No correlation was found between IgG deficiency and infection with SARS-CoV2. The validation of the analysis of IgG-subclasses was successful with quality measurements within the supplier’s intervals. No adjustments will be needed for the reference intervals.

Accurate determination of complement component C1q is hampered by the fact that C1q is an immune complex binding protein. Consequently, immunochemical techniques which rely on immune complex formation in fluid phase such as nephelometry and turbidimetry tend to give results which differ from those obtained by, for example, ELISA and other solid phase-based assays. In this chapter, we discuss the pros and cons of different techniques for the quantification of C1q and present a comprehensive protocol for a newly developed magnetic bead-based sandwich immunoassay which has replaced nephelometry in our complement diagnostic laboratory at the University Hospital in Uppsala., This work was supported by grant 2016-2075-5.1 and 2016-04519 from the Swedish Research Council (VR), the Medical Research Council of Southeast Sweden (FORSS), and by faculty grants from the Linnaeus university. The study was also supported by grants for development and validation of complement assays provided by the University Hospital in Uppsala, Sweden.

Метою даного дослідження є удосконалення методики контролю мутності води технологічного призначення для визначення якості технологічної води методами турбідіметрії та нефелометрії. Для досягнення поставленої мети було сформульовано наступні завдання: – провести дослідження фізико-хімічного складу води як дисперсної вимірювальної фази; – провести огляд методик контролю оптичних показників водної дисперсної фази сучасним вимірювальним обладнанням; – обґрунтувати схемні рішення оптичного аналізатору визначення мутності технічних вод методами турбідиметрії; – провести аналіз складових компонентів вимірювача мутності води технологічного призначення; - обґрунтувати вибір фотодетектора придатного до використання у якості первинного перетворювача вимірювального макету для контролю мутності води технологічного призначення; – розглянути методику вимірювань мутності води технологічного призначення із застосуванням фотодетектору в якості первинного перетворювача. Об’єктом досліджень є дослідження конструктивних особливостей аналізатора придатного для визначення оптичних характеристик мутності досліджуваного водного середовища Предметом дослідження є процес контролю мутності води аналізатором вибраного схемного рішення. Вимірюючи інтенсивність поглинання у водній фазі можна визначити відносний показник забруднення води та мутність водного розчину. Наукова новизна роботи полягає в удосконаленні контролю мутності води технологічного призначення придатної до застосування в технологічних процесах харчової промисловості. Розглянуто схемне рішення аналізатору в ІЧ-області довжин хвиль для контролю мутності води за методикою турбідиметрії та апробовано методику його застосування. Практична цінність. Розглянутий вимірювач мутності води та розроблена для нього методика аналізу наявних у воді твердих домішок придатна для застосування у виробничих процесах харчової промисловості, та забезпечує якісний аналіз води що є вхідною сировиною у технологічних процесах., The purpose of this study is to improve the method of control of turbidity of water for technological purposes to determine the quality of technical water by methods of turbidimetry and nephelometry To achieve this goal, the following tasks were formulated: - to study the physico-chemical composition of water as a dispersed measuring phase; - to review the methods of control of optical parameters of the aqueous dispersed phase by modern measuring equipment; - to substantiate the circuit solutions of the optical analyzer for determining the turbidity of technical waters by turbidimetry; - to analyze the components of the water turbidity meter for technological purposes; - substantiate the choice of a photodetector suitable for use as a primary transducer measuring model to control the turbidity of water for technological purposes; - to develop a method of measuring the turbidity of technical waters using a photodetector of the quality of the primary converter of the measuring model. The object of research is to study the design features of the analyzer suitable for determining the optical characteristics of the turbidity of the studied aquatic environment The subject of the study is the process of water turbidity control by the analyzer of the selected circuit solution. By measuring the intensity of absorption in the aqueous phase, you can determine the relative rate of water pollution and turbidity of the aqueous solution. The scientific novelty of the work is to improve the control of turbidity of technological water suitable for use in technological processes of the food industry. The circuit solution of the analyzer in the IR region of wavelengths for water turbidity control by the method of turbidimetry is considered and the method of its application is tested. Practical value. The considered water turbidity meter and the method of analysis of solid impurities present in water developed for it are suitable for application in production processes of the food indu

Reumatoid artrit (RA) är den vanligaste autoimmuna sjukdomen och prevalensen är 0.5-1.0% av populationen i industriella länder. Diagnos av RA sker bland annat genom analys av markörerna reumatoid faktor (RF) samt antikroppar mot cykliskt citrullinerad peptid (anti-CCP). Nefelometrisk metod samt CMIA har båda varit huvudmetoder för markörerna RF och anti-CCP respektive vid utredning av RA på Laboratoriemedicin på Länssjukhuset Ryhov i Jönköping. Införskaffning av instrumentet Phadia 250 har gjort det möjligt att sammanställa analyserna för markörerna på samma enhet. Syftet med studien var att verifiera EliA-metoden för anti-CCP samt RF på instrumentet Phadia 250 för att kunna ersätta nuvarande analysmetoder för de båda RA-markörerna. Bestämning av cut-off, mellanliggande precision, inomserieprecision samt överensstämmelse med tidigare metod utfördes. Totalt 115 prover (70 blodgivare, 30 patientprover och 15 konsekutiva prover) användes. En korrelation utfördes för CMIA respektive nefelometriska metoden med EliA-metoden samt en kategoriöverensstämmelse för nefelometrisk metod, CMIA och EliA-metoden. God korrelation erhölls för anti-CCP mellan CMIA och EliA-metoden (r=0.953, p=0.001) samt för RF mellan nefelometriska metoden och EliA-metoden (r=0.835, p=0.048). Analys av samtliga markörer bör inkluderas som screening för RA för att upptäcka sjukdomen. Metoden EliA tillät analys av båda markörer och verifieringen möjliggjorde övergången till EliA-metoden för Laboratoriemedicin i Jönköping., Rheumatoid arthritis (RA) is the most common autoimmune disease and the prevalence is 0.5-1.0% among the population in industrial countries. Diagnosis of RA is based partially on detection of the autoantibodies rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (anti-CCP). Nephelometry and CMIA have been the main methods for detection of the antibodies at Laboratoriemedicin at the County Hospital Ryhov in Jönköping. The purpose of this study was to verify the EliA-method for anti-CCP and RF on Phadia 250 in order to replace the current methods with the EliA-method. Determination of cut-off, intermediate precision, within-run precision and consistency with the previous method was performed on a total of 115 samples (70 blood-donors, 30 patient samples and 15 consecutive samples). A correlation between CMIA and the nephelometric method with EliA-method was performed and a cathegorical correspondance was done to assess the accordance between the previous methods with the EliA-method. A good correlation was obtained for anti-CCP between CMIA and the EliA-method (r=0.953, p=0.001) and RF obtained good correlation between the nephelometric method and the EliA-method (r=0.835, p=0.048). Analysis of both markers simultaneously has been recommended and the verification enabled the transition to the EliA-method on Phadia 250 for Laboratoriemedicin in Jönköping.

Резюме. У даній статті оглядово проаналізовано можливості використання методу лазерної нефелометрії (Мюллер-матричної поляризації) у діагностиці структури архітектоніки біотканин, обґрунтовано використання поляризаційних методів дослідження в медицині, що дають нову інформацію про морфологічну й оптико-анізотропну структуру біотканин., Резюме. В данной статье ознакомительно проанализировано возможности использования метода лазерной нефелометрии (Мюллера-матричной поляризации) в диагностике структуры архитектоники биоткани, обосновано использование поляризационных методов исследования в медицине, которые дают новую информацию о морфологической и оптически - анизотропной структуре биоткани., The possibility of using the laser nephelometry (Mueller-matrix polarization) method in the diagnostics of the biotissue architectonics structure is analyzed in this article. The use of polarization methods of research in medicine which provide new information on the morphological and optically anisotropic structure of the tissue is substantiated.

Bakalářská práce se zabývá instrumentálními metodami, které se používají při tvorbě suspenzí a dále stabilizací suspenzí pomocí aditiv. Uvádí informace o povrchově aktivních látkách a alkaloidech a jejich stanovení. Pomocí nefelometrického stanovení byla ověřována účinnost exocelulárního polysacharidu při stabilizaci suspenzí. K zahuštění a stabilizaci vodných systémů byl použit polysacharid od společnosti CP Kelco., The bachelor thesis deals with instrumental methods, used in the formation of a suspensions, further with stabilization of suspensions by additives. It also provides information about the surfactants substances and alkaloids and their determination. The effectivnes of exocellular polysacharide to stabilize suspensions of nephelometric determination was tested. For thickening and stabilizing aqueous systems a polysaccharide from company CP Kelco was used., Fakulta chemicko-technologická

PurposeTo develop an assay to quantify serum immunoglobulin (IgG, IgM, IgA) levels using dried blood spots (DBS) obtained on collection cards to be used as a tool for targeted screening for hypogammaglobulinemia.MethodsDBS samples, along with simultaneous serum samples, were collected from 107 healthy individuals (11 months to 57 years of age). After eluting proteins from DBS, IgG, IgM, and IgA were quantified by an enzyme-linked immunosorbent assay (ELISA). The Ig-DBS assay was validated through calibration curve performance, intra- and inter-assay precision, accuracy, specificity, selectivity, and linearity. The ELISA measurements were compared with serum Ig levels obtained using a standard nephelometry assay on serum samples collected simultaneously with the DBS samples and the results of the two assays were correlated. The stability of IgG, IgM, and IgA in the DBS was tested at room temperature, 36° to 38 °C, 2 to 8 °C, and -25 to -40 °C, from 4 to 14 days.ResultsThe Ig-DBS assay demonstrated precision, accuracy, specificity, selectivity, and linearity. Using the identified correlation coefficients of 0.834 for IgG, 0.789 for IgM, and 0.918 for IgA, the standard nephelometry-based normal reference ranges for all 3 serum Ig isotypes could be used with the Ig-DBS assay in individuals ≥16 years of age. The DBS samples were stable for 14 days at room temperature in a closed polyethylene bag.ConclusionsThe Ig-DBS assay is both sensitive and accurate for quantification of serum immunoglobulins. Samples are sufficiently stable at ambient temperature to allow for convenient shipping and analysis at a centralized laboratory. This assay therefore presents a new option for screening patients ≥16 years of age for hypogammaglobulinemia in any setting.

The mechanisms that contribute to the maintenance of serological memory are still unclear. Rotavirus (RV) memory B cells (mBc) are enriched in IgM + and CD27- subpopulations, which are associated with autoimmune diseases pathogenesis. In patients with autoimmune diseases treated with Rituximab (RTX), some autoantibodies (auto-Abs) decrease after treatment, but other auto-Abs and pathogen-specific IgG Abs remain unchanged. Thus, maintenance of autoimmune and pathogenspecific serological memory may depend on the type of antigen and/or Ab isotype evaluated. Antigen-specific mBc and antigen-specific Abs of different isotypes have not been simultaneously assessed in patients after RTX treatment. To study the relationship between mBc subpopulations and serological memory we characterized total, RV- and tetanus toxoid (TT)-specific mBc by flow cytometry in patients with autoimmune diseases before and after treatment with RTX. We also measured total, RV- and TT-Abs, and some auto-Abs by kinetic nephelometry, ELISA, and EliA tests, respectively. Minor differences were observed between the relative frequencies of RV-mBc in healthy controls and patients with autoimmune disease. After RTX treatment, naïve Bc and total, RV- and TT-specific mBc [IgM+, switched (IgA+/IgG+), IgM+ only, IgD+ only, and CD27- (IgA+/IgG+/IgM+)] were significantly diminished. An important decrease in total plasma IgM and minor decreases in total IgG and IgA levels were also observed. IgM rheumatoid factor, IgG anti-CCP, and IgG anti-dsDNA were significantly diminished. In contrast, RV-IgA, RV-IgG and RV-IgG1, and TT-IgG titers remained stable. In conclusion, in patients with autoimmunity, serological memory against RV and TT seem to be maintained by long-lived plasma cells, unaffected by RTX, and an important proportion of total IgM and serological memory against some auto-antigens seem to be maintained by short-lived plasma cells, dependent on mBc precursors depleted by RTX. © 2014 Herrera et al.

Background: Microalbuminuria is an independent risk factor for cardiovascular morbidity and mortality in the general population. Standard immunochemical urinary albumin assays detect immunoreactive albumin, whereas high-performance liquid chromatography (HPLC) detects both immunoreactive and immunounreactive albumin. Method(s): Using data from the Australian Diabetes, Obesity, and Lifestyle cohort study of randomly selected community-based Australian adults, spot urine samples were tested for albuminuria (spot urine albumin-creatinine ratio [ACR]: normal, <30 mg/g; microalbuminuria, 30 to 300 mg/g; and macroalbuminuria, >300 mg/g) by using both immunonephelometry (IN) and HPLC (n = 10,010). Result(s): Bland-Altman analysis showed significant bias, with a greater ACR by means of HPLC, particularly at lower levels of ACR. Mean ACR was 15.8 mg/g (95% confidence interval [CI], 12.3 to 19.2) by means of IN compared with 30.0 mg/g (95% CI, 27.0 to 35.0) by means of HPLC. The prevalence of microalbuminuria was 4 times greater by means of HPLC compared with IN (20% versus 5.5%). In all demographic and comorbid subgroups associated with microalbuminuria, the prevalence of microalbuminuria increased by 2 to 4 times. A total of 1,743 subjects (17.4%) classified as normoalbuminuric by means of IN were reclassified as microalbuminuric by means of HPLC. Using multivariate logistic regression, women, patients with untreated and treated hypertension, and those with impaired glucose tolerance or diabetes were associated significantly with a change in category from normoalbuminuric to microalbuminuria by means of HPLC. Conclusion(s): HPLC measures significantly more urinary albumin within the normoalbuminuria and microalbuminuria range, resulting in a significant increase in prevalence of microalbuminuria. Longitudinal studies are needed to determine whether the extra individuals identified by means of HPLC are at increased risk for developing hard clinical outcomes (renal and cardio

Background: Urine albumin assays by high-performance liquid chromatography (HPLC) yield greater values than immunoassays at lower albumin levels. We compared predictive values of albumin-creatinine ratios (ACRs) by these 2 techniques for mortality in Aboriginal people. Study Design & Setting: This was a longitudinal study of 741 adults in a remote Aboriginal community who participated in a baseline health survey between 1992 and 1998 at ages ranging from 18 to 84 years (mean, 34 years). All natural deaths were documented on follow-up until 2006. Urine albumin concentrations were measured simultaneously by using both nephelometric and HPLC techniques on baseline urine samples retrieved from -70degreeC storage, as well as creatinine concentrations, and ACRs were derived. Age- and sex-specific tertiles of ACR were compiled. Cox regression analyses were used to evaluate the predictive value of ACR for natural deaths by ACR tertiles and again by z score changes in ACRs as continuous variables. Result(s): Participants were followed up for a median of 11 years, during which a total of 119 natural deaths were documented. ACRs on baseline urine samples were greater by HPLC than immunoassay at lower ACR ranges, but were fairly concordant at levels greater than 100 mg/mmol. Levels of ACR by both techniques were strong predictors of death, but correlations of death with ACR tertiles and with ACR levels on a continuum were similar for the 2 techniques. Limitation(s): The age- and sex-specific tertiles used might introduce some risk of bias in the assessment of predictive value. In addition, assays were performed on urine after more than 10 years of cold storage. Conclusion(s): Despite different absolute values, this study did not show that ACR level by either technique was superior in predicting deaths. © 2008 National Kidney Foundation, Inc.

Bronchiectasis is characterized by chronic airway infection and damage and remains an important health problem. Recent literature has emphasized the role of host defence and immune deficiency in the pathogenesis of bronchiectasis, but there have been few studies of immune function in adult bronchiectasis. A comprehensive screen of immune function was conducted in 103 adult patients with bronchiectasis, encompassing full blood examinations, immunoglobulins and IgG isotypes, complement levels, lymphocyte subsets and neutrophil function. Full blood examinations were normal in this cohort, as were complement levels. Statistical analysis confirmed that a significant number of subjects had low levels of IgG3 (13 patients), B cell lymphocytes (six patients) and T helper cell lymphocytes (seven patients) when compared with controls (P < 0.05). The most common abnormality was found with testing of the neutrophil oxidative burst. All subjects had a normal neutrophil phagocytic function but 33 of the subjects had an oxidative burst that was below the normal range (P < 0001). Almost half the group (45 subjects) had abnormally low levels of one of these four parameters. The findings of low B cells, Th cells and oxidative burst in bronchiectasis are novel. The results emphasize the importance of immune function assessment for adult bronchiectasis. © 2006 British Society for Immunology.

Albuminuria is a risk factor for all-cause mortality. Urinary albumin is traditionally measured with an immunochemical method such as immunonephelometry (IN). High-performance liquid chromatography (HPLC) detects additional albumin that is missed by IN, but it is unknown if HPLC-detected albuminuria also predicts mortality in the general population. We measured urinary albumin at baseline with both IN and HPLC in 10,175 participants in the longitudinal Australian Diabetes, Obesity, and Lifestyle (AusDiab) study. Over 5.2 yr of follow-up, 319 participants died. In a Cox proportional hazards regression model, participants with albuminuria measured by IN or HPLC were approximately twice as likely to die as participants who were normoalbuminuric on both assays. Receiver-operator characteristic curve analyses suggest that each test has a similar ability to predict mortality. However, the HPLC assay provided information on mortality risk that the IN assay did not capture. We conclude that albuminuria, detected by either IN or HPLC, independently predicts mortality in a community-based sample. HPLC identifies some people at increased risk of mortality that IN would not detect. Copyright © 2007 by the American Society of Nephrology.

Nephelometry and turbidimetry are methods based on the phenomenon whereby light, passing through a medium with dispersed particles is attenuated in intensity by scattering. The intensity of the scattered light is measured at right angle (usually, but not necessarily) to the incident light beam (nephelometry) or at a forward angle (turbidimetry). Based on nephelometry and turbidimetry, immunonephelometric and immunoturbidimetric assays for the measurement of proteins have developed and expanded rapidly in recent years, progressively replacing the time-honored gel precipitation techniques. In this study, the theoretical background of light scattering theory, instrumental systems for nephelometry and turbidimetry, the nature and kinetics of the antibody-antigen reaction in fluid, and the application of immunonephelometric and immunoturbidimetric assays for specific proteins in the clinical laboratory are described., Nefelometrija i turbidimetrija su metode koje sa zasnivaju na rasipanju svetlosti: pri prolasku kroz disperzionu sredinu, svetlost se rasipa na česticama disperzione faze. Intenzitet rasute svetlosti može se meriti pod nekim uglom (uobičajeno, ali ne i obavezno, pod pravim uglom), što predstavlja nefelometriju ili u pravcu upadne svetlosti, što predstavlja turbidimetriju. Primenom nefelometrije i turbidimetrije u imunologiji, razvile su se imunonefelometrija i imunoturbidimetrija, kao savremene tehnike za određivanje proteina i peptida, koje su zamenile klasične, dugotrajne, precipitacione tehnike u gelu. U ovom radu objašnjene su teorijske osnove rasipanja svetlosti, prikazane su sheme i delovi instrumenata nefelometra i turbidimetra i opisane su imunonefelometrija i imunoturbidimetrija koje su u širokoj upotrebi u savremenim kliničkim laboratorijama.

Serum or plasma protein electrophoresis is often performed in clinical laboratories to detect and monitor M-components. During the last decade, capillary electrophoresis (CE) has emerged as an interesting alternative to traditional analysis of serum, plasma and urine proteins by agarose gel electrophoresis. We here report a case of pseudoparaproteinemia detected by capillary electrophoresis after Omnipaque™ (iohexol) infusion in a patient with normal kidney function. It is important for the laboratories to be aware of this source of erroneous results and not misclassify it as monoclonal gammopathies.

We present fast, simple immunoturbidimetric assays suitable for direct determination of antibody 'concentration' and 'functionality' in crude samples, such as in-process samples taken at various stages during antibody purification. Both assays display excellent linearity and analytical recovery. Possible influences from commonly employed buffers and salts (present in samples at various concentrations), and of pH variations, were studied for both assays. Interference effects were shown to be negligible for the 'concentration' assay, such that sample pre-treatment prior to assay is unnecessary. The 'functionality' assay displayed concentration dependent sensitivity to interference for ammonium sulphate and Tris(hydroxymethyl)-amino-methane, but was essentially unaffected by all other salts and buffer combinations tested. The immunoturbidimetric assays described here are generically applicable to polyclonal antibodies, require only basic laboratory equipment, are robust, fast, cheap, easy to perform, and readily adapted to automation.

A new operation mode for HPLC-type fluorescence detectors is presented and evaluated using synthetic and environmental particles in the colloidal size range. By applying identical wavelengths for excitation and emission a nephelometric turbidity or single angle light scattering detector is created which can be easily coupled to flow or sedimentation Field-Flow Fractionation (Flow FFF or Sed FFF) for the analysis of colloidal dispersions. The results are compared with standard UV–vis detection methods. Signals obtained are given as a function of particle size and selected detection wavelength. Conclusions can be drawn which affect the current practice of FFF but also for other techniques as groundwater sampling and laboratory column experiments when turbidity is measured in nephelometric mode and in small sample volumes or at low flow rates.

In this report, 27 papers presented at the 1992 Scientific Conference on Obscuration and Aerosol Research are included under the headings of Aerosol Dynamics, Aerosol Characterization Methods, and Optical Properties of Aerosols. Obscurants, Aerosols, Extinction, Transmission, Obscuration, Aerosol, Absorption, Infrared, Scatterings, Sizing, Smoke

Recent field measurements of scattered 3.8 micron laser radiation from naturally occurring aerosols were made during a four-week period in coastal Southern California. Simultaneously, aerosol distribution measurements were made which, in conjunction with Mie scattering theory, gave estimates of the volume scattering coefficient at the various angles. A comparison shows that: (1) Calculated volume scattering coefficients generally decrease more rapidly in angle than measurements indicate; and (2) On the average, the calculation gives factor of 2 larger volume backscattering coefficients than measured, but underpredicts forward scattering by 33%. A second--unrelated--observation of interest: Volume scattering coefficients in the visible showed 65% correlation with 3.8 micron backscatter (177 deg) coefficients. (Author)

[No abstract available]