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.

Immunoglobulins are proteins produced by plasma cells and humans normally produce five different immunoglobulin classes of IgG, IgA, IgM, IgD and IgE. The basic function of the immunoglobulins is to counteract the invasion of pathogenic organisms by their antibody activity and to protect against its toxic products. The basic structure of the immunoglobulins is made up of two identical heavy chains and two light chains, kappa and lambda. In healthy subjects, normal plasma cell contents of the bone marrow are 1-3 %, in patients with multiple myeloma (MM), concentrations increase to over 90 % and are comprised of a malignant transplanted plasma cell clone. This clone of cells produces a kind of immunoglobulin that can be detected using various laboratory methods in both serum and urine. Analysis of free light immunoglobulin chains (kappa and lambda) in human serum occurs in the diagnosis and follow-up of MM and provides a simpler and faster alternative to daily urine collection for the analysis of light immunoglobulin chains in the urine. The purpose of the study was to carry out a method verification of free light chains in serum using an automated immunochemical instrument, BN Prospec II from Siemens, which uses the nephelometric measuring principle (antigen-antibody complex). The calibration concentrations of kappa and lambda assigned by Siemens were met. The method's stability and precision were measured by analyzing high and low controls for both analytes in each of the internal and total series. Within the series received CV 1,47 % for SL1 kappa and 2,57 % for SL2 kappa, and 1,77 % for SL1 lambda and 2,57 % for SL2 lambda. The total series was obtained CV 1,58 % for SL1 kappa and 2,81 % for SL2 kappa and CV 2,05 % for SL1 lambda and 2,30 % for SL2 lambda. The correctness of the method was studied through a patient comparison where 64 patient samples previously analyzed in Lund were analyzed in Kalmar. The study showed good precision and repeatability, the results of the patient comparison showed good correspondence with corresponding methods performed in Lund when the coefficient of determination for S-FLC-kappa was 0, 999 and 0, 958 for S-FLC-lambda. The conclusion is that analysis of free light chains in serum can be used in routine operation in the laboratory for clinical chemistry and transfusion medicine at the county hospital in Kalmar.

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.