ICSH review of internal quality control policy for blood cell counters.

Introduction: This paper is a report of an ICSH review of policies and practices for internal quality control (IQC) policy for haematology cell counters among regulatory bodies, cell counter manufacturers and diagnostic laboratories. It includes a discussion of the study findings and links to separate ICSH guidance for such policies and practices. The application of internal quality control (IQC) methods is an essential pre-requisite for all clinical laboratory testing including the blood count (Full Blood Count, FBC, or Complete Blood Count, CBC).

ICSH guidance for internal quality control policy for blood cell counters.

This paper is a description of the ICSH guidance for internal quality control (IQC) policy for blood cell counters. It follows from and links to a separate ICSH review for such policies and practices. The ICSH has gathered information regarding the current state of practice through review of published guidance from regulatory bodies, a questionnaire to six major cell counter manufacturers and a survey issued to 191 diagnostic laboratories in four countries (China, the Republic of Ireland, Spain, and the United Kingdom) on their IQC practice and approach to the use of commercial IQC materials.

Reference Interval Harmonization: Harnessing the Power of Big Data Analytics to Derive Common Reference Intervals across Populations and Testing Platforms.

Background: Harmonization in laboratory medicine is essential for consistent and accurate clinical decision-making. There is significant and unwarranted variation in reference intervals (RIs) used by laboratories for assays with established analytical traceability. The Canadian Society of Clinical Chemists (CSCC) Working Group on Reference Interval Harmonization (hRI-WG) aims to establish harmonized RIs (hRIs) for laboratory tests and support implementation.

Retrospective analysis of intra-patient laboratory variation demonstrates that the BD Vacutainer® Barricor™ blood collection tube reduces troponin variation.

Objective: The BD Vacutainer® Barricor™ plasma blood collection tube uses a mechanical separator during centrifugation to separate plasma from the cellular elements of blood. Compared to use of plasma separator tubes (PST™) with gel, Barricor™ produces a cleaner sample with less residual cellular content. We sought to determine if Barricor™ reduces pre-analytical error compared to PST™.

Transformation of Sequential Hospital and Outpatient Laboratory Data into Between-Day Reference Change Values.

Background: Serial differences between intrapatient consecutive measurements can be transformed into Taylor series of variation vs time with the intersection at time = 0 (y0) equal to the total variation (analytical + biological + preanalytical). With small preanalytical variation, y0, expressed as a percentage of the mean, is equal to the variable component of the reference change value (RCV) calculation: (CVA2 + CVI2)1/2.

Methods: We determined the between-day RCV of patient data for 17 analytes and compared them to healthy participants' RCVs.

Average of Patient Deltas: Patient-Based Quality Control Utilizing the Mean Within-Patient Analyte Variation.

Background: Because traditional QC is discontinuous, laboratories use additional strategies to detect systematic error. One strategy, the delta check, is best suited to detect large systematic error. The moving average (MA) monitors the mean patient analyte value but cannot equitably detect systematic error in skewed distributions.

Five-Year Two-Center Retrospective Comparison of Central Laboratory Glucose to GEM 4000 and ABL 800 Blood Glucose: Demonstrating the (In)adequacy of Blood Gas Glucose.

Purpose: To evaluate the glucose assays of two blood gas analyzers (BGAs) in intensive care unit (ICU) patients by comparing ICU BGA glucoses to central laboratory (CL) glucoses of almost simultaneously drawn specimens.

Methods: Data repositories provided five years of ICU BGA glucoses and contemporaneously drawn CL glucoses from a Calgary, Alberta ICU equipped with IL GEM 4000 and CL Roche Cobas 8000-C702, and an Edmonton, Alberta ICU equipped with Radiometer ABL 800 and CL Beckman-Coulter DxC. Blood glucose analyzer and CL glucose differences were evaluated if they were both drawn either within ±15 or ±5 minutes.

Analytical Concordance of Diverse Point-of-Care and Central Laboratory Troponin I Assays.

Background: Cardiac troponin I (cTnI) 99th percentile cutoffs, used in the diagnosis of acute myocardial infarction, are not standardized across cTnI assays. We compared 3 point-of-care (POC) and 1 central laboratory contemporary cTnI assays against the Abbott high-sensitivity (hs) cTnI to evaluate the analytical concordance and the feasibility of using a single cutoff value for all assays.

Methods: Fresh blood samples collected from 102 inpatients in the coronary care unit were measured on central laboratory instruments (Beckman Coulter DxI AccuTnI+3 TnI, Abbott Architect hs-TnI) and cTnI POC analyzers (Alere Triage Troponin I, Radiometer AQT90, Abbott i-STAT).

Barricor blood collection tubes are equivalent to PST for a variety of chemistry and immunoassay analytes except for lactate dehydrogenase.

Introduction: The BD Barricor tube uses a novel mechanical separator designed to eliminate gel artifacts, decrease cellular contamination, and improve stability. Here, we evaluated the Barricor tube as a possible replacement for PST using Beckman Coulter analyzers under both optimal, alternative, and suboptimal centrifugation conditions based on BD recommendations.

Methods: Paired PST and Barricor samples were collected from 4 local hospitals and processed based on site-specific preanalytical systems involving automated or manual centrifugation.

Low sensitivity of anion gap to detect clinically significant lactic acidosis in the emergency department.

Introduction: Lactic acidosis represents the pathologic accumulation of lactate and hydrogen ions. It is important to efficiently diagnose lactic acidosis as delayed treatment will lead to poor patient outcomes. As plasma lactate levels may not be rapidly available, some physicians may use elevated anion gaps to test for the need to measure lactate.

National Survey of Adult and Pediatric Reference Intervals in Clinical Laboratories across Canada: A Report of the CSCC Working Group on Reference Interval Harmonization.

Objective: Reference intervals are widely used decision-making tools in laboratory medicine, serving as health-associated standards to interpret laboratory test results. Numerous studies have shown wide variation in reference intervals, even between laboratories using assays from the same manufacturer. Lack of consistency in either sample measurement or reference intervals across laboratories challenges the expectation of standardized patient care regardless of testing location.

The BD Barricor blood collection tube is an acceptable and robust alternative to the PST for use with the Beckman AccuTnI+3 assay.

Objectives: BD Canada recently released a blood collection tube with a novel mechanical separator called the Barricor. We evaluated this tube as an alternate sample type for cardiac troponin I (cTnI) testing using the Beckman Coulter AccuTnI+3 assay.

Design And Methods: 3014 paired patient specimens (Barricor, plasma separator tube or PST) were obtained from the emergency departments and cardiac care units of nine hospitals in and around Edmonton, Alberta.

Impaired clinical utility of sequential patient GEM blood gas measurements associated with calibration schedule.

Background: Within- and/or between-instrument variation may falsely indicate patient trends or obscure real trends. We employ a methodology that transforms sequential intra-patient results into estimates of biologic and analytic variation. We previously derived realistic biologic variation (s) of blood gas (BG) and hematology analytes.

Requirements for Successful Adoption of a Glucose Measurement System Into a Hospital POC Program.

Widespread and successful implementation of any glucose measurement system in a hospital point-of-care (POC) program requires a number of features in addition to accurate and reliable analytical performance. Such features include, but are not limited to, a system's glucose-hematocrit dependence, durability, information technology capabilities, and battery capacity and battery life. While the study of Ottiger et al in this issue supports the analytical accuracy and reliability of Bayer's CONTOUR XT® blood glucose monitoring system, the suitability of other features of this system for a hospital POC program remains to be established.

The use of serial outpatient complete blood count (CBC) results to derive biologic variation: a new tool to gauge the acceptability of hematology testing.

Introduction: Most estimates of biologic variation (sb ) are based on periodically acquiring and storing specimens from reference subjects, followed by analysis within a tightly controlled analytic run. We demonstrate that reliable estimates of sb can be derived for virtually all constituents of the CBC from previously obtained paired patient results and summary QC data.

Methods: A laboratory data repository provided all of the outpatient CBC results measured over 20.

The Glucose Measurement Industry and Hemoglobin A1c: An Opportunity for Creative Destruction.

The MyStar Extra self-monitoring blood glucose (SMBG) system provides moving estimates of the patient's hemoglobin A1c (HbA1c). There is a treasure trove of highly accurate glucose data available from highly accurate SMBG, CGM and FGM along with highly accurate HPLC HbA1c. If Nathan's criteria are used to select subjects whose glucoses can be correlated to the HbA1c, then algorithms can be developed for robustly transforming glucose into HbA1c.

The prediction of postoperative stroke or death in patients with preoperative atrial fibrillation undergoing non-cardiac surgery: a VISION sub-study.

Background: The optimal means of pre-operative risk stratification in patients with atrial fibrillation (AF) is uncertain.

Objective: To examine the accuracy of AF thromboembolic risk models (the CHADS2, CHA2DS2-VASc, and R2CHADS2 scores) for predicting 30-day stroke and/or all-cause mortality after non-cardiac surgery in patients with preoperative AF, and to compare these risk scores with the Revised Cardiac Risk Index (RCRI).

Patients/methods: A multicentre (8 countries, 2007-2011) prospective cohort study of patients ≥ 45 years of age undergoing inpatient non-cardiac surgery, who were followed until 30 days after surgery.

Quality control of automated cell counters.

The hematology analyzers of today provide more reproducible analyses compared with those of a few decades ago, necessitating an evolution in hematology quality practices. The improved performance allows use of simple quality control rules. This improved performance also renders the repeat analysis of critical value specimens non value added.

Urinary metal concentrations among female welders.

As part of a Canada-wide study of women entering non-traditional trades [Women's Health in Apprenticeship Trades-Metalworkers and Electricians (WHAT-ME)], we examined spot urine samples from women welders in Alberta to determine whether urinary metal concentrations exceeded those of the general population, to compare levels to previously published urinary concentrations in male welders and to examine the relationship with welding tasks. Women mailed-in urine samples collected close to the time of completing a detailed exposure questionnaire, including welding tasks on their most recent day welding at work. Of 53 welders working in their trade, 45 had urinary creatinine >0.