Method comparison of three serum free light chain assays on the Roche Cobas 6000 c501 chemistry analyzer

Objectives Free light chains (FLC) are important in the diagnosis, prognosis and monitoring of therapy response of patients with monoclonal gammopathies. In this study, we performed a method comparison of three FLC assays on the Cobas 6000 c501 chemistry analyzer of Roche Diagnostics. Methods Samples of 119 patients with various monoclonal gammopathies and 26 control patients were measured with the Freelite (The Binding Site), Diazyme (Diazyme Laboratories) and KLoneus (Trimero Diagnostics) FLC assays. A method comparison was performed and reference intervals of the three assays were validated. Results The analysis of the Bland-Altman agreement showed bias between the three FLC assays, ranging from −62.7 to 5.1% for κFLC and between −29.2 to 80.5% for λFLC. The Freelite and Diazyme assays have the highest agreement. The concordance of the FLC-ratio ranges from 41 to 75%, with the highest concordance between the Freelite and KLoneus assays. The FLC-ratio in 25 sera from healthy controls were within the reference ranges of the Freelite and KLoneus assays. The FLC-ratio was elevated in all 25 samples tested with the Diazyme assay. Conclusions The agreement for the free light chains is highest between the Freelite and the Diazyme assay and fair for the KLoneus assay. However, concordance of the FLC-ratio is highest when the Freelite and KLoneus assays were compared. Our data suggest that concordance for the Diazyme assay could be improved by recalibration. Because of absolute differences between the three methods in individual patients, none of the three FLC assays can be used interchangeably.

An evaluation of the performance of the Point of Care Test iCHROMA™ AFP method: Precision and accuracy

The estimation of serum alpha-fetoprotein (AFP) is useful in the diagnosis and monitoring of primary hepatocellular carcinoma, hepatoblastoma, non-seminomatous testicular germ cell tumours and other germ cell tumours. The iCHROMA™ AFP is a lateral flow chromatography, fluorescence immunoassay (FIA) for the quantitative determination of AFP in serum or plasma. In this study, the Boditech iCHROMA™ AFP assay had a very good precision of 9.8%. It showed a very good correlation with the following 12 methods: Abbott Architect (r2 = 0.9705), BioMerieux VIDAS (r2 = 0.9717), Roche Cobas 6000/8000 (r2 = 0.9738), Siemens Centaur XP/XPT/Classic (r2 = 0.9654), Siemens/DPC/Immulite 2000/2500 (r2 = 0.9673), Siemens/DPC/Immulite 1000 (r2 = 0.9670), Beckman Dxl 600/800 (r2 = 0.9676), Roche Elecsys (r2 = 0.9683), Roche Cobas 4000/e411 (r2 = 0.9688), Roche Modular E170 (r2 = 0.9692), SNIBE Maglumi (r2 = 0.9457) and Ortho Vitros 3600/5600/ECi (r2 = 0.9714). In summary, the iCHROMA™ AFP, a rapid point of care test method, has a within-run precision value of less than 10% and excellent correlations with traditional laboratory methods. There is a consistent overestimation with the iCHROMA™ method, which must be taken into consideration when setting a reference range.

Analytical comparison between two automated biochemical analyzer systems: Roche Cobas 8000 and Mindray BS2000M

Summary Background. The values of biomarkers play a central role in routine clinical decision-making. Whereas, the performances of different automated chemical analyzers remain unclear. To determine the performances of different platforms, we evaluated the capability between Roche Cobas 8000 and Mindray BS2000M. Methods. A total of 1869 remaining serum samples were collected. CK, LDH-1, RBP, Cys-c, IgA, IgM and IgG were assessed by using paired-t test, Passing-Bablok regression analysis and Bland Altman analysis according to CLSI EP5-A3. Results. There were significant in average bias of all items between two machines (P < 0.001). Due to the 95% confidence interval of intercept A included 0, CK, LDH-1, Cys-c and IgG were not show systemic error in Passing-Bablok regression analysis. Except for IgA, the r values and correlation coefficient of all items were higher than 0.91, which showed that the correlation and consistency is good. The Bland-Altman analysis showed that two instruments had more than 95% of the points apart from CK, LDH-1, and IgA. Conclusions. It can be considered that the two instruments have good correlation and consistency in CK, LDH-1, RBP, Cys-c, IgM and IgG, and the two instruments are interchangeable and can replace each other.

A Comprehensive HPV-STI NGS Assay for Detection of 29 HPV Types and 14 non-HPV Sexually Transmitted Infections

Sexually transmitted infections (STIs) are prevalent throughout the world and impose a significant burden on individual health and public health systems. Missed diagnosis and late treatment of STIs can lead to serious complications such as infertility and cervical cancer. Although sexually transmitted co-infections are common, most commercial assays target one or a few STIs. The HPV-STI ChapterDx Next Generation Sequencing (NGS) assay detects and quantifies 29 HPVs and 14 other STIs in a single-tube and single-step PCR reaction and can be applied to tens to thousands of samples in a single sequencing run. The assay was evaluated in this study, and the limit of detection was 100% at 50 copies for all targets, and 100%, 96%, 88% at 20 copies for 34, 8, and 1 target, respectively. The performance of this assay has been compared to Roche cobas HPV test, showing an overall agreement of 97.5% for hr-HPV, and 98.5% for both, HPV16 and HPV18. The assay also detected all HPV-infected CIN2/3 with 100% agreement with Roche cobas HPV results. Moreover, several co-infections with non-HPV STIs, such as C. trachomatis, T. vaginalis, M. genitalium, and HSV2 were identified. The Chap-terDx HPV-STI NGS assay is a user-friendly, easy to automate and cost-efficient assay, which provides accurate and comprehensive results for a wide spectrum of HPVs and STIs.

Gender-specific reference intervals for serum prolactin concentrations before and after precipitation by polyethylene glycol

Prolactin, a hormone secreted by the anterior pituitary, exists in three major forms in circulation. The macroprolactin form is biologically inactive but contributes to elevated serum prolactin concentrations. Precipitation of macroprolactin by polyethylene glycol (PEG) is widely used in clinical laboratories for the screening of macroprolactin. The aim of this study was two-fold. Firstly, we sought to establish locally relevant reference intervals for serum prolactin and post-PEG precipitation prolactin concentrations in both genders on the Roche Cobas Prolactin II electrochemiluminescence immunoassay. Secondly, the prolactin concentrations after precipitation by PEG dissolved in phosphate-buffered saline (post-PEG(PBS)) were compared with those after precipitation by PEG dissolved in deionised water (PEG(diH2O)). Prolactin concentrations were measured by using the Prolactin Gen II assay on a Roche Cobas e601 analyser. Recoveries of prolactin after precipitation by PEG in PBS and PEG in diH2O were 64.7%–115.8% and 60.9–100.8%, respectively. Post-PEG (PBS) prolactin concentrations were not statistically different from post-PEG (diH2O) prolactin concentrations in either gender.

Comparison of real-time RT-PCR and RT-PCR/MALDI-TOF methods for SARS-CoV-2 detection in saliva

Background The coronavirus disease 2019 pandemic has accelerated the need for rapid validation and implementation of assays for detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in diagnostic specimens. Multiple molecular methods have received emergency use authorization by the U.S. Food and Drug Administration for detection of SARS-CoV-2 in upper respiratory specimens, with testing of nasopharyngeal (NP) specimens serving as the foundation for these assays. However, supply chain constraints and the need for improved ease and safety of collection have prompted consideration of other specimen types as alternatives to NP specimens for detection of SARS-CoV-2. Here, we compared two methods for SARS-CoV-2 detection in saliva: the Roche cobas® 6800 SARS-CoV-2 real-time RT-PCR Test (“Roche”), which tests for viral ORF1ab (target 1, T1) and envelope E genes (target 2, T2); and the Agena Biosciences MassARRAY® SARS-CoV-2 Panel/MassARRAY® System (“Agena”), which tests for targets in the ORF1ab gene (ORF1, Orf1ab) and nucleocapsid N gene (N1, N2, N3). Methods Sixty saliva specimens collected within 48 hours of SARS-CoV-2 detection in an upper respiratory (anterior nares or NP) specimen from the same individual were tested in both the Roche and Agena platforms. Each system was evaluated for overall detection results and agreement with results of matched upper respiratory specimens. In addition, we determined the limit of detection (LoD) for each system and its component targets using an in-house SARS-CoV-2 standard generated from pooled positive saliva specimens quantitated against a commercially available standard (ZeptoMetrix NATSARS(COV2)-ERC). Results Both platforms demonstrated a similarly high sensitivity (97%) and specificity (100%) when compared to matched patient upper respiratory specimens and had high agreement with one another (Cohen’s κ = 0.9321, p = 2.6x10-13). Overall, the LoD (copies/mL) for the Roche assay was four times lower than that of Agena for saliva specimens (390.6 v. 1562.5). Furthermore, we determined that the LoD differed among the target components of each assay. The experimental LoD was comparable across Roche targets, but probit analyses indicate T2 has greater sensitivity (LoD: 228.6), Of the five Agena targets, the N2 target had the lowest LoD (1562.5). Conclusions In sum, we demonstrate that saliva is an acceptable specimen for testing in both the Roche cobas® 6800 SARS-CoV-2 real-time RT-PCR Test and the Agena Biosciences MassARRAY® SARS-CoV-2 Panel/MassARRAY® System, and both provide sensitive and specific detection of SARS-CoV-2 in saliva specimens. Although there was a high level of agreement between platforms, the LoD was lower for the Roche compared to the Agena assay with T2 and N2 being the most sensitive targets on each platform, respectively. The addition of saliva as an acceptable specimen and understanding the sensitivity for testing on these platforms can further inform public health measures for screening and detection to combat the pandemic.