Search

Serum ferritin is currently the recommended laboratory test to investigate iron deficiency. There have been efforts to standardise serum ferritin assays with implementation of traceability to the World Health Organization reference standard. We evaluate the analytical bias among five widely used commercial ferritin assays in Australia. The relationship between serum ferritin and erythrocyte parameters was recently explored to derive functional reference limits. Residual patient serum specimens were analysed by five participating laboratories that utilised a different ferritin assay, Abbott, Beckman Coulter, Roche, Siemens, and Ortho. Using data mining approach, functional reference limits for Siemens, Abbott, and Ortho serum ferritin methods were derived and compared. At clinically relevant ferritin decision points, compared to the Beckman method, the Roche assay showed higher results ranging from 6 mug/L (31%) at the lowest decision point to 575 mug/L (57%) at the highest decision point. In contrast, the Ortho method underestimated ferritin results at lower decision points of 20 and 30 mug/L, with estimated ferritin results of 16 mug/L (-19%) and 27 mug/L (-12%), respectively. The Abbott and Siemens assays showed a positive bias which was introduced at differing decision points. The comparison of the Siemens and Ortho methods presents similar inflection points between the two assays in the establishment of functional reference limits for serum ferritin. There remain significant biases among some of the commonly used commercial ferritin assays in Australia. More studies are needed to assess if functional reference limits are a way to overcome method commutability issues.Copyright © 2021 Royal College of Pathologists of Australasia

JAK2-Val617Phe mutation detection involves Taqman allele-specific-probe-based assay generating cycle threshold (Ct) values for wild-type(WT)/Val617Phe(VF). Quantitative BCR-ABL-p210 involves real-time-PCR assay producing Ct values (ABL and BCR-ABL copy numbers). After thermal cycling run, data analysis involves manually exporting raw quantitation data as spreadsheet file and formatting it to include amplification thresholds checks and insertion of several calculation formulas. Calculations/checks include: (JAK2-Val617Phe) input limit, grey zone, delta Ct (VF-WT) for each sample; (BCR-ABL-p210) Ct replicates variation, normalised copy numbers (standardisation to international scale). Manual checks/calculations may take a scientist up to 15-20 minutes with risk of transcription/analytical errors (wrong Results). Aim(s): To develop/validate an 'automated' spreadsheet which analyses raw data from JAK2-Val617Phe and quatitative-BCR-ABL-p210 assays and provides final data with minimal manual work. Method(s): Automated spreadsheets were developed for JAK2-Val617Phe and quatitative-BCR-ABL-p210, using 20 data sets from previous manual-entry spreadsheets. They involved multiple modifications (complex formulas) for error-free/robust spreadsheets. Spreadsheets were validated using further 20 data sets each. Result(s): Data from 'automated' spreadsheets fully agreed with manual-entry spreadsheets during validation. Each analysis took less than 5 minutes. Multiple simulations demonstrated spreadsheets were modification-protected. Discussion(s): Molecular haematology testing has significant clinical implications (diagnosis/management). Use of 'automated' spreadsheets minimises laboratory errors and improves analysis time.Copyright © 2018

Case: A 92-year-old female with past history of dementia presented to hospital after an unwitnessed fall. She was diagnosed with rhabdomyolysis with serum total creatine kinase (CK) of 618 U/L (RR 0-190). However, six weeks later, her serum CK remained unchanged with no significant rise or fall. Cardiac cause for elevated CK was considered. Serum troponin was normal. Serum CKMB by immunoinhibition method was 945 U/L and unexpectedly higher than total CK. Methods and Results: Polyethylene glycol (PEG) precipitation study showed clearly reduced recovery in CK value post-PEG in our patient specimen suggesting presence of macro CK (patient, baseline 476 U/L, post-PEG 138 U/L; control specimen 1, baseline 546 U/L, post-PEG 440 U/L; control specimen 2, baseline 368 U/L, post-PEG 328 U/L). CK electrophoresis showed the predominant CK isoenzyme band (94% of total activity) lying at the electrophoretic mobility usually associated with CKMB. Macro CK can overlie the CKMB band. Gel filtration chromatography was not available to sub-classify the macro CK into type 1 or 2. Discussion(s): Macro CK type 1 may occur in healthy people but is also associated with autoimmune disease. Macro CK type 2 has been reported in mainly ill patients and is associated with malignancy.1 Reference1. Galarraga B, Sinclair D, Fahie-Wilson MN, et al. A rare but important cause for a raised serum creatine kinase concentration: two case reports and a literature review. Rheumatology 2003; 42: 186-8.Copyright © 2018

Introduction: Between-laboratory variation in the quantification of co-migrating paraproteins in the beta-region of serum protein electrophoresis may adversely impact patient care if the patient uses different pathology services. To identify the level of agreement in the reporting of beta-migrating paraproteins, sample exchanges were conducted in five Australian states and New Zealand (NZ). Method(s): A minimum of four samples containing beta-migrating paraproteins were distributed to participating laboratories. Laboratories were invited to report paraprotein concentration using their routine practice and measure involved total immunoglobulin (Ig) using immunochemical methods. Victorian laboratories were requested to also report 'total beta + paraprotein' by densitometry. Result(s): Thirty-one laboratories returned results. Overall, CVs for quantification of the involved total Ig by immunochemical methods performed better than what was routinely reported in the paraprotein field (1.5-13.7% vs 8.2-21.8% for NSW; 4.1-9.0% vs 13-28.6% for NZ; 7.4-29.4% vs 5.7-67.0% for qld; 0.7-7.3% vs 18.2-43.3% for WA; 0.2-7.2% vs 0-23.6% for SA; and 3.2-9.7% vs 13.8-70.5% for VIC). Amongst Victorian laboratories, CVs for 'total beta+paraprotein' quantification were better than what was reported in the paraprotein field (4.0-18.2% vs 13.8-70.5%). Conclusion(s): This study has highlighted the between-laboratory variation in measurement of beta-migrating paraproteins and the need for harmonisation to improve patient care.Copyright © 2018

Gonadal hormones impact bone health and higher values of sex hormone-binding globulin (SHBG) have been independently associated with fracture risk in men without chronic kidney disease. People with chronic kidney disease have a greatly increased fracture risk, and gonadal dysfunction is common in men receiving dialysis treatment. Nevertheless, in these men the effect of gonadal steroids and SHBG on bone mineral density (BMD) and fracture risk is unknown. Here we investigate relationships between gonadal steroids, SHBG, BMD and fracture in men on long-term dialysis therapy, awaiting kidney or simultaneous pancreas kidney transplantation. Results of serum biochemistry, SHBG, gonadal steroids (total testosterone, calculated free testosterone and estradiol), BMD by dual-energy X-ray absorptiometry and thoracolumbar X-rays were obtained. Multivariable regression models were used to examine associations between SHBG, gonadal steroids, BMD and fracture of 321 men with a mean age of 47 years. Diabetes mellitus was present in 45% and their median dialysis vintage was 24 months. Prior fractures occurred in 42%, 18% had vertebral fracture on lateral spine X-ray, 17% had non-vertebral fragility fracture within 10 years and 7% had both. After adjustment for age, body mass index and dialysis vintage, higher SHBG levels were significantly associated with nonvertebral fractures [odds ratio 1.81 (1.30-2.53)] and remained significant after adjustment for BMD. Calculated free testosterone and estradiol values were not associated with fracture. Prevalent fracture rates were high in relatively young men on dialysis awaiting transplantation. Thus, SHBG is a novel biomarker associated with fracture, which warrants investigation in prospective studies.Copyright © 2018 International Society of Nephrology