Assessment of analytical bias in ferritin assays and impact on functional reference limits.

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 µg/L (31%) at the lowest decision point to 575 µg/L (57%) at the highest decision point. In contrast, the Ortho method underestimated ferritin results at lower decision points of 20 and 30 µg/L, with estimated ferritin results of 16 µg/L (-19%) and 27 µg/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.

Parallel processing and maintaining adequate alignment between instruments and methods.

Parallel processing of laboratory tests across more than one instrument platform: permits dealing with increasing workloads; but broadens uncertainty of measurement; minimising measurement uncertainty means keeping assay performances continuously aligned. Important questions are: Why is there the need to demonstrate "acceptable alignment" between methods/instruments? What methods/tools can be used to test method/instrument alignment and how adjustments can be made? What is an "acceptable" alignment? How often should alignments be checked and what is the reasoning for this?

Quality assessment of interpretative commenting in clinical chemistry.

BACKGROUND: Clinical interpretation of laboratory results is an integral part of clinical chemistry. However, the performance goals for assessing interpretative commenting in this discipline have not been as well established as for the quality of analytical requirements. METHODS: We present a review of the 10 case reports circulated in the 2002 Patient Report Comments Program by the Royal College of Pathologists of Australasia (RCPA) and the Australasian Association of Clinical Biochemists Chemical Pathology Group of RCPA-Quality Assurance Programs Pty Ltd. Participants were expected to add an interpretative comment to a set of results accompanied by brief clinical details. Comments received were broken down into components that were translated into key phrases. An expert panel evaluated the appropriateness of the key phrases and proposed a suggested composite comment. A case summary/rationale was also returned to participants. RESULTS: There was considerable diversity in the range of interpretative comments received for each case report. Although the majority of comments received were felt to be acceptable by the expert panel, some comments were felt to be inappropriate, misleading, or in a few instances, dangerous. CONCLUSION: The golden rule in medicine is "do no harm". Although there is no objective evidence that interpretive comments help to improve patient outcomes, if comments are added to reports it is important that they reflect accepted practice and current guidelines. It is of concern that a large proportion of comments returned were considered to be inappropriate and/or misleading. The Patient Report Comments Program has highlighted the need to consider limiting commenting to persons with clear expertise.

A discussion of cases in the 2001 RCPA-AQAP Chemical Pathology Case Report Comments Program.

AIM: We present a descriptive analysis of the 10 case reports distributed in the Royal College of Pathologists of Australasia (RCPA) and the Australasian Association of Clinical Biochemists (AACB) Chemical Pathology Patient Report Comments Program to assess the quality of interpretative commenting in clinical biochemistry in 2001. METHOD: Participants were asked to comment on a given set of biochemistry results attached with brief clinical details. All responses received were translated into key phrases and graphically presented on a histogram. An expert panel was asked to evaluate the appropriateness of the key phrases and to propose a suggested composite comment. RESULTS: While the majority of comments received were felt to be acceptable by the expert panel, some comments were felt to be inappropriate or misleading. As comments on laboratory reports may affect clinical management of patients, it is important that these comments reflect accepted practice and current guidelines. CONCLUSION: The Patient Report Comments Program may play an important role in continuing education and possibly in quality assurance of interpretative commenting.