Sharing reference intervals and monitoring patients across laboratories - findings from a likely commutable external quality assurance program.

OBJECTIVES: Laboratory results are increasingly interpreted against common reference intervals (CRIs), published clinical decision limits, or previous results for the same patient performed at different laboratories. However, there are no established systems to determine whether current analytical performance justifies these interpretations. We analysed data from a likely commutable external quality assurance program (EQA) to assess these interpretations. METHODS: The use of CRIs was assessed by evaluating instrument group medians against minimum specifications for bias. The use of clinical decision limits was assessed using specifications from professional bodies, and the monitoring of patients by testing at different laboratories was assessed by comparing all-laboratory imprecision to within-subject biological variation. RESULTS: Five of the 18 analytes with Australasian CRIs did not meet specification for all instrument groups. Among these, calcium and magnesium failed for one instrument group out of seven, while bicarbonate, chloride, and lipase failed for two instrument groups. Of the 18 analytes reviewed currently without CRIs in Australasia, 10 candidates were identified. Among analytes with clinical decision limits, i.e. lipids, glucose, and vitamin D, only triglycerides met both bias and imprecision specifications, while vitamin D met the imprecision specification. Monitoring patients by testing at different laboratories was supported for 15 of the 46 (33 %) analyte-method principles groups that met minimum imprecision specifications. CONCLUSIONS: Analysis of data from commutable EQA programs can provide a mechanism for monitoring whether analytical performance justifies the interpretations made in contemporary laboratory practice. EQA providers should establish systems for routinely providing this information to the laboratory community.

Quality assurance programs for vitamin A and E in serum: are we doing enough to assess laboratory performance?

OBJECTIVES: Monitoring serum vitamin A (retinol) and vitamin E (α-tocopherol) concentrations is common practice for assessing nutritional status. Measurement of these vitamins can be challenging due to several factors. Whilst the RCPAQAP Vitamins: Serum Program assists participating laboratories in harmonisation, the materials provided do not contain the analogues of retinol and α-tocopherol that may be present in real patient samples. We aimed to assess participants' capacity to accurately report retinol and α-tocopherol in the presence of the vitamin E analogues tocopherol acetate and γ-tocopherol. METHODS: A supplementary series of a control sample and three matched spiked samples were distributed to each laboratory participating in the Program. Retinol and α-tocopherol results for each spiked sample were compared to the results of the control sample submitted by each participant. Acceptability of retinol and α-tocopherol results was determined based on the RCPAQAP allowable performance specifications (APS). RESULTS: Thirteen participants returned results for the supplementary sample series. Interference from α-tocopherol acetate was observed with results below the APS in 30 % (n=4) of laboratories for retinol quantification and in 23 % (n=3) for α-tocopherol quantification. One laboratory returned results above the APS for α-tocopherol when γ-tocopherol was present. CONCLUSIONS: This supplementary sample series has shown that the presence of vitamin E analogues can lead to the over or under estimation of nutritional status by some participants. Affected laboratories are encouraged to review their analytical procedures. To further assess laboratory competence, EQA providers should consider using patient samples or spiked challenge samples.

Ensuring quality in 17OHP mass spectrometry measurement: an international study assessing isomeric steroid interference.

OBJECTIVES: Interference from isomeric steroids is a potential cause of disparity between mass spectrometry-based 17-hydroxyprogesterone (17OHP) results. We aimed to assess the proficiency of mass spectrometry laboratories to report 17OHP in the presence of known isomeric steroids. METHODS: A series of five samples were prepared using a previously demonstrated commutable approach. These samples included a control (spiked to 15.0 nmol/L 17OHP) and four challenge samples further enriched with equimolar concentrations of 17OHP isomers (11α-hydroxyprogesterone, 11ß-hydroxyprogesterone, 16α-hydroxyprogesterone or 21-hydroxyprogesterone). These samples were distributed to 38 participating laboratories that reported serum 17OHP results using mass spectrometry in two external quality assurance programs. The result for each challenge sample was compared to the control sample submitted by each participant. RESULTS: Twenty-six laboratories (68 % of distribution) across three continents returned results. Twenty-five laboratories used liquid chromatography-tandem mass spectrometry (LC-MS/MS), and one used gas chromatography-tandem mass spectrometry to measure 17OHP. The all-method median of the control sample was 14.3 nmol/L, ranging from 12.4 to 17.6 nmol/L. One laboratory had results that approached the lower limit of tolerance (minus 17.7 % of the control sample), suggesting the isomeric steroid caused an irregular result. CONCLUSIONS: Most participating laboratories demonstrated their ability to reliably measure 17OHP in the presence of the four clinically relevant isomeric steroids. The performance of the 12 (32 %) laboratories that did not engage in this activity remains unclear. We recommend that all laboratories offering LC-MS/MS analysis of 17OHP in serum, plasma, or dried bloodspots determine that the isomeric steroids are appropriately separated.

Recent advances of small extracellular vesicle biomarkers in breast cancer diagnosis and prognosis.

Current clinical tools for breast cancer (BC) diagnosis are insufficient but liquid biopsy of different bodily fluids has recently emerged as a minimally invasive strategy that provides a real-time snapshot of tumour biomarkers for early diagnosis, active surveillance of progression, and post-treatment recurrence. Extracellular vesicles (EVs) are nano-sized membranous structures 50-1000 nm in diameter that are released by cells into biological fluids. EVs contain proteins, nucleic acids, and lipids which play pivotal roles in tumourigenesis and metastasis through cell-to-cell communication. Proteins and miRNAs from small EVs (sEV), which range in size from 50-150 nm, are being investigated as a potential source for novel BC biomarkers using mass spectrometry-based proteomics and next-generation sequencing. This review covers recent developments in sEV isolation and single sEV analysis technologies and summarises the sEV protein and miRNA biomarkers identified for BC diagnosis, prognosis, and chemoresistance. The limitations of current sEV biomarker research are discussed along with future perspective applications.

Radiation doses and fractionation schedules in non-low-risk ductal carcinoma in situ in the breast (BIG 3-07/TROG 07.01): a randomised, factorial, multicentre, open-label, phase 3 study.

BACKGROUND: Whole breast irradiation (WBI) after conservative surgery for ductal carcinoma in situ (DCIS) reduces local recurrence. We investigated whether a tumour bed boost after WBI improved outcomes, and examined radiation dose fractionation sensitivity for non-low-risk DCIS. METHODS: The study was an international, randomised, unmasked, phase 3 trial involving 136 participating centres of six clinical trials organisations in 11 countries (Australia, New Zealand, Singapore, Canada, the Netherlands, Belgium, France, Switzerland, Italy, Ireland, and the UK). Eligible patients were women aged 18 years or older with unilateral, histologically proven, non-low-risk DCIS treated by breast-conserving surgery with at least 1 mm of clear radial resection margins. They were assigned to one of four groups (1:1:1:1) of no tumour bed boost versus boost after conventional versus hypofractionated WBI, or randomly assigned to one of two groups (1:1) of no boost versus boost after each centre prespecified conventional or hypofractionated WBI. The conventional WBI used was 50 Gy in 25 fractions, and hypofractionated WBI was 42·5 Gy in 16 fractions. A boost dose of 16 Gy in eight fractions, if allocated, was delivered after WBI. Patients and clinicians were not masked to treatment allocation. The primary endpoint was time to local recurrence. This trial is registered with ClinicalTrials.gov (NCT00470236). FINDINGS: Between June 25, 2007, and June 30, 2014, 1608 patients were randomly assigned to have no boost (805 patients) or boost (803 patients). Conventional WBI was given to 831 patients, and hypofractionated WBI was given to 777 patients. Median follow-up was 6·6 years. The 5-year free-from-local-recurrence rates were 92·7% (95% CI 90·6-94·4%) in the no-boost group and 97·1% (95·6-98·1%) in the boost group (hazard ratio 0·47; 0·31-0·72; p<0·001). The boost group had higher rates of grade 2 or higher breast pain (10% [8-12%] vs 14% [12-17%], p=0·003) and induration (6% [5-8%] vs 14% [11-16%], p<0·001). INTERPRETATION: In patients with resected non-low-risk DCIS, a tumour bed boost after WBI reduced local recurrence with an increase in grade 2 or greater toxicity. The results provide the first randomised trial data to support the use of boost radiation after postoperative WBI in these patients to improve local control. The international scale of the study supports the generalisability of the results. FUNDING: National Health and Medical Research Council of Australia, Susan G Komen for the Cure, Breast Cancer Now, OncoSuisse, Dutch Cancer Society, Canadian Cancer Trials Group.

Comparison Study of Small Extracellular Vesicle Isolation Methods for Profiling Protein Biomarkers in Breast Cancer Liquid Biopsies.

Small extracellular vesicles (sEVs) are an important intercellular communicator, participating in all stages of cancer metastasis, immunity, and therapeutic resistance. Therefore, protein cargoes within sEVs are considered as a superior source for breast cancer (BC) biomarker discovery. Our study aimed to optimise the approach for sEV isolation and sEV proteomic analysis to identify potential sEV protein biomarkers for BC diagnosis. sEVs derived from BC cell lines, BC patients' plasma, and non-cancer controls were isolated using ultracentrifugation (UC), a Total Exosome Isolation kit (TEI), and a combined approach named UCT. In BC cell lines, the UC isolates showed a higher sEV purity and marker expression, as well as a higher number of sEV proteins. In BC plasma samples, the UCT isolates showed the highest proportion of sEV-related proteins and the lowest percentage of lipoprotein-related proteins. Our data suggest that the assessment of both the quantity and quality of sEV isolation methods is important in selecting the optimal approach for the specific sEV research purpose, depending on the sample types and downstream analysis.

One-Electron Quantum Cyclotron as a Milli-eV Dark-Photon Detector.

We propose using trapped electrons as high-Q resonators for detecting meV dark photon dark matter. When the rest energy of the dark photon matches the energy splitting of the two lowest cyclotron levels, the first excited state of the electron cyclotron will be resonantly excited. A proof-of-principle measurement, carried out with one electron, demonstrates that the method is background free over a 7.4 day search. It sets a limit on dark photon dark matter at 148 GHz (0.6 meV) that is around 75 times better than previous constraints. Dark photon dark matter in the 0.1-1 meV mass range (20-200 GHz) could likely be detected at a similar sensitivity in an apparatus designed for dark photon detection.

Moving towards the optimization of diagnosis for patients with sarcoma: A 10-year review of externally consulted sarcoma cases in a general anatomical pathology service.

INTRODUCTION: Soft tissue sarcomas (STS) are rare, diagnostically challenging, malignant tumors with diverse histomorphologic, immunohistochemical and molecular features. In our practice, STS are reported in a general anatomical pathology practice with no formal subspecialized training in reporting these complex specimens. Our study was performed to look at the rate of external consultation (EC), along with other parameters including discordance rate, associated diagnostic delay with EC and extent of secondary work-up performed by the consultant for correct diagnosis. METHODS: The reports from 880 soft tissue sarcomas cases in the province of Saskatchewan between January 1, 2010, and December 31, 2020, were analyzed descriptively. RESULTS: Of the 880 cases reviewed in our database, 51.9% (n = 457) cases were sent to 35 different North American institutions for expert opinion. The initial diagnosis and expert opinion were in full agreement for 182 cases (39.8%), while 194 cases (42.5%) had partial agreement and 66 cases (14.4%) had zero agreement. Of the cases that had zero agreement, 20 cases (4.4%) were initially diagnosed as malignant, with a benign opinion given by the expert; and 10 cases (2.2%) were initially diagnosed as benign, which were malignant upon expert review. CONCLUSION: Soft tissue sarcomas are complex tumors that frequently require expert opinion and integration of ancillary techniques with histomorphologic features for definitive classification. A multidisciplinary, subspecialized approach to STS and availability of necessary ancillary tests would improve diagnostic accuracy. In centers where the case load would not support the full-time expertise of an STS multidisciplinary team, criteria should be developed to effectively utilize EC practices.

Erratum: Muons in Supernovae: Implications for the Axion-Muon Coupling [Phys. Rev. Lett. 125, 051104 (2020)].

This corrects the article DOI: 10.1103/PhysRevLett.125.051104.

Search for Axionlike Dark Matter Using Solid-State Nuclear Magnetic Resonance.

We report the results of an experimental search for ultralight axionlike dark matter in the mass range 162-166 neV. The detection scheme of our Cosmic Axion Spin Precession Experiment is based on a precision measurement of ^{207}Pb solid-state nuclear magnetic resonance in a polarized ferroelectric crystal. Axionlike dark matter can exert an oscillating torque on ^{207}Pb nuclear spins via the electric dipole moment coupling g_{d} or via the gradient coupling g_{aNN}. We calibrate the detector and characterize the excitation spectrum and relaxation parameters of the nuclear spin ensemble with pulsed magnetic resonance measurements in a 4.4 T magnetic field. We sweep the magnetic field near this value and search for axionlike dark matter with Compton frequency within a 1 MHz band centered at 39.65 MHz. Our measurements place the upper bounds |g_{d}|<9.5×10^{-4} GeV^{-2} and |g_{aNN}|<2.8×10^{-1} GeV^{-1} (95% confidence level) in this frequency range. The constraint on g_{d} corresponds to an upper bound of 1.0×10^{-21} e cm on the amplitude of oscillations of the neutron electric dipole moment and 4.3×10^{-6} on the amplitude of oscillations of CP-violating θ parameter of quantum chromodynamics. Our results demonstrate the feasibility of using solid-state nuclear magnetic resonance to search for axionlike dark matter in the neV mass range.

CD44 variant 6 is associated with prostate cancer growth and chemo-/radiotherapy response in vivo.

We have previously demonstrated that CD44 variant 6 (CD44v6) is associated with prostate cancer (CaP) growth and therapeutic resistance in vitro, however, the role of CD44v6 in CaP in vivo is not fully understood. The purpose of this study is to investigate the effect of CD44v6 on CaP growth and chemo-/radiotherapy response in NOD/SCID mouse models in vivo and to validate its role as a therapeutic target for CaP therapy. CD44v6 was knocked down in PC-3M CaP cell line using short hairpin RNA. Subcutaneous (s.c.) and orthotopic CaP mouse xenografts were established. The effect of CD44v6 knockdown (KD) on tumour growth was evaluated in both s.c. and orthotopic models. Chemo-/radiotherapy response was evaluated in the s.c. model. Association of CD44v6 with PI3K/Akt pathway was validated using immunohistochemistry staining. We found that KD of CD44v6 significantly reduced tumour growth in both models, and enhanced the sensitivity of tumours to chemotherapy and radiotherapy in the s.c. model. In addition, we demonstrated that KD of CD44v6 is associated with downregulation of the PI3K/Akt/mTOR pathway. Our data confirm that CaP growth and chemo-/radiosensitivity in vivo is associated with CD44v6, which holds great promises as a therapeutic target in the treatment of CaP.

Muons in Supernovae: Implications for the Axion-Muon Coupling.

The high temperature and electron degeneracy attained during a supernova allow for the formation of a large muon abundance within the core of the resulting protoneutron star. If new pseudoscalar degrees of freedom have large couplings to the muon, they can be produced by this muon abundance and contribute to the cooling of the star. By generating the largest collection of supernova simulations with muons to date, we show that observations of the cooling rate of SN 1987A place strong constraints on the coupling of axionlike particles to muons, limiting the coupling to g_{aµ}<10^{-8.1} GeV^{-1}.

Influence of isotopically labeled internal standards on quantification of serum/plasma 17α-hydroxyprogesterone (17OHP) by liquid chromatography mass spectrometry.

Objectives Our recent survey of 44 mass spectrometry laboratories across 17 countries identified variation in internal standard (IS) choice for the measurement of serum/plasma 17α-hydroxyprogesterone (17OHP) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The choice of IS may contribute to inter-method variations. This study evaluated the effect of two common isotopically labeled IS on the quantification of 17OHP by LC-MS/MS. Methods Three collaborating LC-MS/MS laboratories from Asia, Europe and Australia, who routinely measure serum 17OHP, compared two IS, (1) IsoSciences carbon-13 labeled 17OHP-[2,3,4-13C3], and (2) IsoSciences deuterated 17OHP-[2,2,4,6,6,21,21,21-2H]. This was performed as part of their routine patient runs using their respective laboratory standard operating procedure. Results The three laboratories measured 99, 89, 95 independent samples, respectively (up to 100 nmol/L) using the 13C- and 2H-labeled IS. The slopes of the Passing-Bablok regression ranged 0.98-1.00 (all 95% confidence interval [CI] estimates included the line of identity), and intercept of <0.1 nmol/L. Average percentage differences of -0.04% to -5.4% were observed between the two IS materials, which were less than the optimal bias specification of 7% determined by biological variation, indicating no clinically significant difference. The results of 12 Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) proficiency samples (1-40 nmol/L) measured by the laboratories were all within the RCPAQAP analytical performance specifications for both IS. Conclusions Overall, the comparison between the results of 13C- and 2H-labeled IS for 17OHP showed good agreement, and show no clinically significant bias when incorporated into the LC-MS/MS methods employed in the collaborating laboratories.

Constraining Primordial Black Hole Abundance with the Galactic 511 keV Line.

Models in which dark matter consists entirely of primordial black holes (PBHs) with masses around 10^{17} g are currently unconstrained. However, if PBHs are a component of the Galactic dark matter density, they will inject a large flux of energetic particles into the Galaxy as they radiate. Positrons produced by these black holes will subsequently propagate throughout the Galaxy and annihilate, contributing to the Galactic 511 keV line. Using measurements of this line by the INTEGRAL satellite as a constraint on PBH positron injection, we place new limits on PBH abundance in the mass range 10^{16}-10^{17} g, ruling out models in which these PBHs constitute the entirety of dark matter.

Search for Axionlike Dark Matter with a Liquid-State Nuclear Spin Comagnetometer.

We report the results of a search for axionlike dark matter using nuclear magnetic resonance (NMR) techniques. This search is part of the multifaceted Cosmic Axion Spin Precession Experiment program. In order to distinguish axionlike dark matter from magnetic fields, we employ a comagnetometry scheme measuring ultralow-field NMR signals involving two different nuclei (^{13}C and ^{1}H) in a liquid-state sample of acetonitrile-2-^{13}C (^{13}CH_{3}CN). No axionlike dark matter signal was detected above the background. This result constrains the parameter space describing the coupling of the gradient of the axionlike dark matter field to nucleons to be g_{aNN}<6×10^{-5} GeV^{-1} (95% confidence level) for particle masses ranging from 10^{-22} eV to 1.3×10^{-17} eV, improving over previous laboratory limits for masses below 10^{-21} eV. The result also constrains the coupling of nuclear spins to the gradient of the square of the axionlike dark matter field, improving over astrophysical limits by orders of magnitude over the entire range of particle masses probed.

Inhibition of PI3K/Akt/mTOR signaling pathway alleviates ovarian cancer chemoresistance through reversing epithelial-mesenchymal transition and decreasing cancer stem cell marker expression.

BACKGROUND: Ovarian cancer is the most common malignant tumor of the female reproductive tract. Chemoresistance is a major challenge for current ovarian cancer therapy. However, the mechanism underlying epithelial ovarian cancer (EOC) chemoresistance is not completely uncovered. The phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling is an important intracellular pathway in regulating cell cycle, quiescence, and proliferation. The aim of this study is to investigate the role of PI3K/Akt/mTOR signaling pathway and its association with epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) marker expression in EOC chemoresistance. METHODS: The expressions of EMT and CSC markers were detected by immunofluorescence, western blot, and quantitative real-time PCR. BEZ235, a dual PI3K/mTOR inhibitor, was employed to investigate the role of PI3K/Akt/ mTOR signaling in regulating EMT and CSC marker expression. Students' t test and one-way ANOVA with Tukey's post-hoc test were used to compare the data from different groups. RESULTS: We found that EMT and CSC marker expression were significantly enhanced in chemoresistant EOC cells, which was accompanied by the activation of PI3K/Akt/mTOR signaling. Compared with single cisplatin treatment, combined treatment with BEZ235 and cisplatin significantly disrupted the colony formation ability, induced higher ROS level and more apoptosis in chemoresistant EOC cells. Furthermore, the combination approach effectively inhibited PI3K/Akt/mTOR signaling pathway, reversed EMT, and decreased CSC marker expression in chemoresistant EOC cells compared with cisplatin mono-treatment. CONCLUSIONS: Our results first demonstrate that EMT and enhanced CSC marker expression triggered by activated PI3K/Akt/mTOR signaling are involved in the chemoresistance of EOC, and BEZ235 in combination with cisplatin might be a promising treatment option to reverse EOC chemoresistance.

In Vivo 3D MRI Measurement of Tumour Volume in an Orthotopic Mouse Model of Prostate Cancer.

Prostate cancer (CaP) is the most commonly diagnosed cancer in males in western countries. Orthotopic implantation is considered as an ideal xenograft model for CaP study, and noninvasive measurement of tumor volume changes is important for monitoring responses to anticancer therapies. In this study, the T2-weighted fast spin echo sequence magnetic resonance imaging (MRI) was performed on a CaP orthotopic non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mouse model weekly for 6 weeks post PC-3 CaP cell inoculation, and the fat signal was suppressed using a chemical shift-selective pulse. Subsequently, the MRI data were imported into the image processing software Avizo Standard and stacked into three-dimensional (3D) volumes. Our results demonstrate that MRI, combined with 3D reconstruction, is a feasible and sensitive method to assess tumor growth in a PC-3 orthotopic CaP mouse model and this established monitoring approach is promising for longitudinal observation of CaP xenograft development after anticancer therapy in vivo. Further investigation is needed to validate this protocol in a larger cohort of mice to generate enough statistical power.

Effect of fish meal supplementation on luteal sensitivity to intrauterine infusions of prostaglandin F2α in the bovine.

Progesterone is a steroid hormone secreted from the corpus luteum (CL), which is responsible for establishment and maintenance of pregnancy. Early embryonic mortality often occurs due to inadequate regulation of uterine prostaglandin (PG) F2α secretion, leading to a decrease in progesterone and loss of pregnancy. The objective of the current study was to determine the effects of fish meal supplementation on luteal sensitivity to intrauterine infusions of PGF2α. Nonlactating beef cows received corn gluten meal or fish meal supplementation for 60 days. Cows were administered four intrauterine infusions of 0.25 mL saline at 6-h intervals (n = 6 corn gluten meal; n = 5 fish meal) or two doses of 0.5 mg PGF2α in 0.25 mL saline at 12-h intervals (n = 11 corn gluten meal; n = 11 fish meal) commencing on days 10 to 12 of the estrous cycle. At time of each infusion, luteal biopsies were collected to determine the effects of supplementation on expression of immediate early and steroidogenic genes involved in cholesterol transport and progesterone biosynthesis. Transrectal ultrasonography was performed to measure diameter of CL, and blood samples were collected to determine serum progesterone. Intrauterine infusion of PGF2α resulted in upregulation or no change in FOS, NR4A1, and 3BHSD and downregulation in LDLR, STARD1, and CYP11A1. Although CL diameter decreased, infusion of PGF2α resulted in functional regression in 91% of cows supplemented with corn gluten meal, and only 46% for fish meal supplemented animals. Results demonstrate that fish meal supplementation alters luteal sensitivity to PGF2α, which may affect fertility.

Epithelial cell adhesion molecule (EpCAM) is involved in prostate cancer chemotherapy/radiotherapy response in vivo.

BACKGROUND: Development of chemo-/radioresistance is a major challenge for the current prostate cancer (CaP) therapy. We have previously demonstrated that epithelial cell adhesion molecule (EpCAM) is associated with CaP growth and therapeutic resistance in vitro, however, the role of EpCAM in CaP in vivo is not fully elucidated. Here, we aimed to investigate how expression of EpCAM is involved in CaP growth and chemo-/radiotherapy response in NOD/SCID mouse models in vivo and to validate its role as a therapeutic target for CaP therapy. METHODS: EpCAM was knocked down in PC-3 CaP cell line using short hairpin RNA (shRNA). The effect of EpCAM-knockdown (KD) on tumour growth, chemo-/radiotherapy response and animal survival was evaluated on subcutaneous (s.c) and orthotopic mouse models. RESULTS: We found that KD of EpCAM significantly inhibited tumour growth, increased xenograft sensitivity to chemotherapy/radiotherapy, and prolonged the survival of tumour-bearing mice. In addition, we demonstrated that KD of EpCAM is associated with downregulation of the PI3K/Akt/mTOR pathway. CONCLUSIONS: In conclusion, our data confirms that CaP growth and chemo-/radioresistance in vivo is associated with over-expression of EpCAM, which serves both a functional biomarker and promising therapeutic target.

Can a combination of average of normals and "real time" External Quality Assurance replace Internal Quality Control?

Internal Quality Control and External Quality Assurance are separate but related processes that have developed independently in laboratory medicine over many years. They have different sample frequencies, statistical interpretations and immediacy. Both processes have evolved absorbing new understandings of the concept of laboratory error, sample material matrix and assay capability. However, we do not believe at the coalface that either process has led to much improvement in patient outcomes recently. It is the increasing reliability and automation of analytical platforms along with improved stability of reagents that has reduced systematic and random error, which in turn has minimised the risk of running less frequent IQC. We suggest that it is time to rethink the role of both these processes and unite them into a single approach using an Average of Normals model supported by more frequent External Quality Assurance samples. This new paradigm may lead to less confusion for laboratory staff and quicker responses to and identification of out of control situations.