Limitations of glycated albumin standardization when applied to the assessment of diabetes patients.

OBJECTIVES: Glycated albumin (GA) has potential value in the management of people with diabetes; however, to draw meaningful conclusions between clinical studies it is important that the GA values are comparable. This study investigates the standardization of the Norudia Glycated Albumin and Lucica Glycated Albumin-L methods. METHODS: The manufacturer reported imprecision was verified by performing CLSI-EP15-A3 protocol using manufacturer produced controls. The Japanese Clinical Chemistry Reference Material (JCCRM)611-1 was measured 20 times to evaluate the accuracy of both methods. GA was also measured in 1,167 patient samples and results were compared between the methods in mmol/mol and %. RESULTS: Maximum CV for Lucica was ≤0.6 % and for Norudia ≤1.8 % for control material. Results in mmol/mol and % of the JCCRM611-1 were within the uncertainty of the assigned values for both methods. In patient samples the relative difference in mmol/mol between the two methods ranged from -10.4 % at a GA value of 183 mmol/mol to +8.7 % at a GA value of 538 mmol/mol. However, the relative difference expressed in percentage units ranged from of 0 % at a GA value of 9.9 % to +1.7 % at a GA value of 30 %. CONCLUSIONS: The results in mmol/mol between the two methods for the patient samples were significantly different compared to the results in %. It is not clear why patient samples behave differently compared to JCCRM611-1 material. Valuable lessons can be learnt from comparing the standardization process of GA with that of HbA1c.

Comparator Data Characteristics and Testing Procedures for the Clinical Performance Evaluation of Continuous Glucose Monitoring Systems.

Comparing the performance of different continuous glucose monitoring (CGM) systems is challenging due to the lack of comprehensive guidelines for clinical study design. In particular, the absence of concise requirements for the distribution of comparator (reference) blood glucose (BG) concentrations and their rate of change (RoC) that are used to evaluate CGM performance, impairs comparability. For this article, several experts in the field of CGM performance testing have collaborated to propose characteristics of the distribution of comparator measurements that should be collected during CGM performance testing. Specifically, it is proposed that at least 7.5% of comparator BG concentrations are <70 mg/dL (3.9 mmol/L) and >300 mg/dL (16.7 mmol/L), respectively, and that at least 7.5% of BG-RoC combinations indicate fast BG changes with impending hypo- or hyperglycemia, respectively. These proposed characteristics of the comparator data can facilitate the harmonization of testing conditions across different studies and CGM systems and ensure that the most relevant scenarios representing real-life situations are established during performance testing. In addition, a study protocol and testing procedure for the manipulation of glucose levels are suggested that enable the collection of comparator data with these characteristics. This work is an important step toward establishing a future standard for the performance evaluation of CGM systems.

Glucose measurements with accu check inform II versus hexokinase plasma method during surgery under general anesthesia, an observational cohort study.

PURPOSE: Limited research exists on translation of in-vitro glucose measurement interfering compounds to the in-vivo situation. We investigated whether Point-of-Care glucose measurements by Accu Chek Inform II (ACI II) were accurate to monitor glucose concentrations during surgery with general anesthesia by comparing with the reference laboratory hexokinase plasma glucose test. METHOD: Patients undergoing surgery with general anesthesia were included. Anesthesia was maintained with either Sevoflurane or Total intravenous anesthesia (TIVA). Prior to and after induction, blood glucose was measured with ACI II and the hexokinase test. Bland-Altman analysis was performed to assess method agreement. Subgroup analyses on glucose measurement differences per type of maintenance anesthesia were performed. RESULTS: Thirty-nine patients were included, and 78 measurements were performed. All paired measurements had clinically acceptable agreement with a percentage error of 10.0% (95% CI 8.0 to 11.9). The mean difference (95% limits of agreement) between ACI II and hexokinase for all measurements was 0.0 mmol/L (-0.7 to 0.7 mmol/L). Before induction (n = 39), mean difference was -0.1 mmol/L (-0.6 to 0.4 mmol/L), and after induction (n = 39), mean difference was 0.1 mmol/L (-0.8 to 0.9 mmol/L). Further investigation showed the difference varied per test for patients receiving Sevoflurane compared to patients receiving TIVA (-0.2 ± 0.4 mmol/L vs. 0.4 ± 0.3 mmol/L, p < 0.001). Before and after induction, the difference between ACI II and hexokinase measurements increased for patients receiving Sevoflurane compared to patients receiving TIVA (0.4 ± 0.4 mmol/L vs. -0.4 ± 0.3 mmol/L, p < 0.001). CONCLUSION: The agreement between glucose measurements using ACI II and the reference laboratory hexokinase test was clinically acceptable with a percentage error of 10.0% (95% CI 8.0 to 11.9). The use of TIVA may negatively affect the measurement performance of the ACI II.

Consequences of different cut-off values for high-sensitivity cardiac troponin for risk stratification of patients suspected for NSTE-ACS with a modified HEART score.

Aim: This study aims to enhance prehospital risk assessment for suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) patients using the HEART-score. By incorporating novel point-of-care high-sensitivity cardiac troponin devices, a modified HEART-score was developed and compared with the conventional approach. Patients & methods: Troponin points within the modified HEART-score are based on values below the limit of quantitation (LoQ), between the LoQ and 99th percentile and above the 99th percentile of the used device. A total HEART-score of three or lower is considered low-risk for major adverse cardiac events. Results & conclusion: The number of low-risk patients decreased based on the modified HEART-score. The sensitivity and negative predictive value increased which suggests increasing safety in ruling out patients with suspected NSTE-ACS.

Clinical Performance Evaluation of Continuous Glucose Monitoring Systems: A Scoping Review and Recommendations for Reporting.

The use of different approaches for design and results presentation of studies for the clinical performance evaluation of continuous glucose monitoring (CGM) systems has long been recognized as a major challenge in comparing their results. However, a comprehensive characterization of the variability in study designs is currently unavailable. This article presents a scoping review of clinical CGM performance evaluations published between 2002 and 2022. Specifically, this review quantifies the prevalence of numerous options associated with various aspects of study design, including subject population, comparator (reference) method selection, testing procedures, and statistical accuracy evaluation. We found that there is a large variability in nearly all of those aspects and, in particular, in the characteristics of the comparator measurements. Furthermore, these characteristics as well as other crucial aspects of study design are often not reported in sufficient detail to allow an informed interpretation of study results. We therefore provide recommendations for reporting the general study design, CGM system use, comparator measurement approach, testing procedures, and data analysis/statistical performance evaluation. Additionally, this review aims to serve as a foundation for the development of a standardized CGM performance evaluation procedure, thereby supporting the goals and objectives of the Working Group on CGM established by the Scientific Division of the International Federation of Clinical Chemistry and Laboratory Medicine.

Referral decisions based on a pre-hospital HEART score in suspected non-ST-elevation acute coronary syndrome: final results of the FamouS Triage study.

AIMS: Although pre-hospital risk stratification of patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) by ambulance paramedics is feasible, it has not been investigated in daily practice whether referral decisions based on this risk stratification is safe and does not increase major adverse cardiac events (MACE). In Phase III of the FamouS Triage study, it was investigated whether referral decisions by ambulance paramedics based on a pre-hospital HEART score, is non-inferior to routine management. METHODS AND RESULTS: FamouS Triage Phase III is a non-inferiority study, comparing the occurrence of MACE before (Phase II) and after (Phase III) implementation of referral decisions based on a pre-hospital HEART score. In Phase II, all patients were risk-stratified and referred to the hospital; in Phase III, low-risk patients (HEART score ≤ 3) were not referred. Primary endpoint was MACE (acute coronary syndrome, revascularization, or death) within 45 days. A total of 1236 patients were included. Mean age was 63 years, 43% were female, 700 patients were included in the second phase and 536 in the third phase in which 149 low-risk patients (28%) were not transferred to the hospital. Occurrence of 45 days MACE was 16.6% in Phase II and 15.7% in Phase III (P = 0.67). Percentage MACE in low-risk patients was 2.9% in Phase II and 1.3% in Phase III. After adjustments for differences in baseline variables, the hazard ratio of 45 days MACE in Phase III was 0.88 (95% confidence interval 0.63-1.25) as compared to Phase II. CONCLUSION: Pre-hospital risk stratification of patients with suspected NSTE-ACS, avoiding hospitalization of a substantial number of low-risk patients, seems feasible and non-inferior to transferring all patients to the hospital.

Pre-hospital versus hospital acquired HEART score for risk classification of suspected non ST-elevation acute coronary syndrome.

INTRODUCTION: Although increasing evidence shows that in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) both hospital and pre-hospital acquired HEART (History, ECG, Age, Risk factors, Troponin) scores have strong predictive value, pre-hospital and hospital acquired HEART scores have never been compared directly. METHODS: In patients with suspected NSTE-ACS, the HEART score was independently prospectively assessed in the pre-hospital setting by ambulance paramedics and in the hospital by physicians. The hospital HEART score was considered the gold standard. Low-risk (HEART score ≤3) was considered a negative test. Endpoint was occurrence of major adverse events within 45 days. RESULTS: A total of 699 patients were included in the analyses. In 516 (74%) patients pre-hospital and hospital risk classification was similar, in 50 (7%) pre-hospital risk classification was false negative (45 days mortality 0%) and in 133 (19%) false positive (45 days mortality 1.5%). False negative risk classifications were caused by differences in history (100%), risk factor assessment (66%) and troponin (18%) and were more common in older patients. Occurrence of major adverse events was comparable in pre-hospital and hospital low-risk patients (2.9% vs. 2.7%, p = 0.9). Incidence of major adverse events was 0% in the true negative group, 26% in the true positive group, 10% in the false negative group and 5% in the false positive group. Predictive value of both pre-hospital and hospital acquired HEART scores was high, although the 'area under the curve' of hospital acquired HEART score was higher (0.84 vs. 0.74, p < 0.001). CONCLUSION: In approximately 25% of patients hospital and pre-hospital HEART score risk classifications disagree, mainly by risk overestimation in the pre-hospital group. Since disagreement is primarily caused by different scoring of history and risk factors, additional training may improve pre-hospital scoring.

Standardization process of continuous glucose monitoring: Traceability and performance.

People with diabetes are required to regularly check their glucose to make therapy decisions. So far, systems for self-monitoring of blood glucose were used, but nowadays minimally invasive continuous glucose monitoring (CGM) systems are increasingly more often employed, sometimes to partially replace self-monitoring of blood glucose. Most CGM systems on the market measure glucose concentrations continuously in the interstitial fluid of the subcutaneous fatty tissue. However, CGM has a principle limitation. Collecting interstitial fluid frequently in sufficiently large volumes over short time periods is not easy. As a consequence, no internationally accepted reference measurement procedure is currently available for glucose in interstitial fluid which is a prerequisite to achieve an optimal metrological traceability. Recent studies indicate that the analytical performance of minimally invasive CGM systems differs not only between manufacturers but also between individual sensors of the same system, sometimes even in the same subject. Because manufacturers don't provide detailed information about the traceability chain and the measurement uncertainty of their systems glucose values obtained with CGM can currently not be adequately traced to higher-order standards or methods. Therefore, the Working Group on Continuous Glucose Monitoring aims at establishing a traceability chain for minimally invasive CGM systems, as well as procedures and metrics for the assessment of their analytical performance.

Referral decisions based on a prehospital HEART score in suspected non-ST-elevation acute coronary syndrome: design of the FamouS Triage 3 study.

Background: It is not yet investigated whether referral decisions based on prehospital risk stratification of non-ST-elevation Acute Coronary Syndrome (NSTE-ACS) by the complete History, ECG, Age, Risk factors and initial Troponin (HEART) score are feasible and safe. Hypothesis: Implementation of referral decisions based on the prehospital acquired HEART score in patients with suspected NSTE-ACS is feasible and not inferior to routine management in the occurrence of major adverse cardiac events within 45 days. Study design & methods: FamouS Triage 3 is a feasibility study with a before-after sequential design. The aim is to assess whether prehospital HEART-score management including point-of-care troponin measurement is feasible and noninferior to routine management. Primary end point is the occurrence of major adverse cardiac events within 45 days. Conclusion: If referral decisions based on prehospital acquired risk stratification are feasible and noninferior this can become the new prehospital management in suspected NSTE-ACS.

Impact of elevated HbA1c on long-term mortality in patients presenting with acute myocardial infarction in daily clinical practice: insights from a 'real world' prospective registry of the Zwolle Myocardial Infarction Study Group.

BACKGROUND: Long-term clinical outcome is less well known in up to presentation persons unknown with diabetes mellitus who present with acute myocardial infarction and elevated glycosylated haemoglobin (HbA1c) levels on admission. We aimed to study the prognostic impact of deranged HbA1c at presentation on long-term mortality in patients not known with diabetes, presenting with acute myocardial infarction. METHODS: A single-centre, large, prospective observational study in patients with and without known diabetes admitted to our hospital for ST-segment elevation myocardial infarction (STEMI) and non-STEMI. Newly diagnosed diabetes mellitus was defined as HbA1c of 48 mmol/l or greater and pre-diabetes mellitus was defined as HbA1c between 39 and 47 mmol/l. The primary endpoint was all-cause mortality at short (30 days) and long-term (median 52 months) follow-up. RESULTS: Out of 7900 acute myocardial infarction patients studied, 1314 patients (17%) were known diabetes patients. Of the 6586 patients without known diabetes, 3977 (60%) had no diabetes, 2259 (34%) had pre-diabetes and 350 (5%) had newly diagnosed diabetes based on HbA1c on admission. Both short-term (3.9% vs. 7.4% vs. 6.0%, p<0.001) and long-term mortality (19% vs. 26% vs. 35%, p<0.001) for both pre-diabetes patients as well as newly diagnosed diabetes patients was poor and comparable to known diabetes patients. After multivariate analysis, newly diagnosed diabetes was independently associated with long-term mortality (hazard ratio 1.72, 95% confidence interval 1.27-2.34, P=0.001). CONCLUSIONS: In the largest study to date, newly diagnosed or pre-diabetes was present in 33% of acute myocardial infarction patients and was associated with poor long-term clinical outcome. Newly diagnosed diabetes (HbA1c ⩾48 mmol/mol) is an independent predictor of long-term mortality. More attention to early detection of diabetic status and initiation of blood glucose-lowering treatment is necessary.

Pre-hospital risk assessment in suspected non-ST-elevation acute coronary syndrome: A prospective observational study.

BACKGROUND: Pre-hospital risk stratification of non-ST-elevation acute coronary syndrome (NSTE-ACS) by the complete HEART score has not yet been assessed. We investigated whether pre-hospital risk stratification of patients with suspected NSTE-ACS using the HEART score is accurate in predicting major adverse cardiac events (MACE). METHODS: This is a prospective observational study, including 700 patients with suspected NSTE-ACS. Risk stratification was performed by ambulance paramedics, using the HEART score; low risk was defined as HEART score ⩽ 3. Primary endpoint was occurrence of MACE within 45 days after inclusion. Secondary endpoint was myocardial infarction or death. RESULTS: A total of 172 patients (24.6%) were stratified as low risk and 528 patients (75.4%) as intermediate to high risk. Mean age was 53.9 years in the low risk group and 66.7 years in the intermediate to high risk group (p<0.001), 50% were male in the low risk group versus 60% in the intermediate to high risk group (p=0.026). MACE occurred in five patients in the low risk group (2.9%) and in 111 (21.0%) patients at intermediate or high risk (p<0.001). There were no deaths in the low risk group and the occurrence of acute myocardial infarction in this group was 1.2%. In the high risk group six patients died (1.1%) and 76 patients had myocardial infarction (14.4%). CONCLUSIONS: In suspected NSTE-ACS, pre-hospital risk stratification by ambulance paramedics, including troponin measurement, is accurate in differentiating between low and intermediate to high risk. Future studies should investigate whether transportation of low risk patients to a hospital can be avoided, and whether high risk patients benefit from immediate transfer to a hospital with early coronary angiography possibilities.

Accuracy of pre-hospital HEART score risk classification using point of care versus high sensitive troponin in suspected NSTE-ACS.

INTRODUCTION: Pre-hospital risk classification by the HEART score is performed with point of care troponin assessment. However, point of care troponin is less sensitive than high sensitive troponin measurement which is used in the hospital setting. In this study we compared pre-hospital HEART-score risk classification using point of care troponin versus high sensitive troponin. METHODS: In 689 consecutive patients with suspected NSTE-ACS, point of care troponin and laboratory high-sensitive troponin were measured in pre-hospital derived blood. For every patient the HEART score with both point of care troponin (HEART-POC) and high sensitive troponin (HEART-hsTnT) was determined. Endpoint was MACE within 45 days. RESULTS: Mean age was 64 (SD ±â€¯14), 163 (24%) patients were considered low-risk by HEART-hsTnT and 170 (25%) by HEART-POC. MACE was observed in 17%. Although high sensitive versus POC troponin scoring was different in 130 (19%) of patients, in 678 (98%) patients risk classification in low versus intermediate-high risk was similar. The predictive values of HEART-POC versus HEART-HsTnT was similar (AUC 0.75 versus 0.76, p = 0.241). CONCLUSION: Although high sensitive versus POC troponin scoring was dissimilar in one fifth of patients, this resulted in different patient risk classification in only 2 percent of patients. Therefore POC troponin measurement suffices for pre-hospital risk stratification of suspected NSTE-ACS.

In-Hospital Healthcare Utilization, Outcomes, and Costs in Pre-Hospital-Adjudicated Low-Risk Chest-Pain Patients.

BACKGROUND: There is increasing evidence that in patients presenting with acute chest pain, pre-hospital triage can accurately identify low-risk patients. It is, however, still unclear which diagnostics are performed in pre-hospital-adjudicated low-risk patients and what the contribution is of those diagnostic results in the healthcare process. OBJECTIVES: The aim of this study was to quantify healthcare utilization, costs, and outcomes in pre-hospital-adjudicated low-risk chest-pain patients, and to extrapolate to total costs in the Netherlands. METHODS: This was a prospective cohort study including 700 patients with suspected non-ST-elevation acute coronary syndrome in which pre-hospital risk stratification using the HEART score was performed by paramedics. Low risk was defined as a pre-hospital HEART score ≤ 3. Data on (results of) hospital diagnostics, costs, and discharge diagnosis were collected. RESULTS: A total of 172 (25%) patients were considered as low risk. Of these low-risk patients, the mean age was 54 years, 52% were male, and 84% of patients were discharged within 12 h. Repeated electrocardiography and routine laboratory measurements, including cardiac markers, were performed in all patients. Chest X-ray was performed in 61% and echocardiography in 11% of patients. After additional diagnostics, two patients (1.2%) were diagnosed as non-ST-elevation myocardial infarction and two patients (1.2%) as unstable angina. Other diagnoses were atrial fibrillation (n = 1) and acute pancreatitis/cholecystitis (n = 2); all other patients had non-specific/non-acute discharge diagnoses. Mean in-hospital costs per patient were €1580. The estimated yearly acute healthcare cost in low-risk chest-pain patients in the Netherlands is €30,438,700. CONCLUSION: In low-risk chest-pain patients according to pre-hospital risk assessment, acute healthcare utilization and costs are high, with limited added value. Possibly, if a complete risk assessment can be performed by ambulance paramedics, acute hospitalization of the majority of low-risk patients is not necessary, which can lead to substantial cost reduction. TRIAL ID: Dutch Trial Register [http://www.trialregister.nl]: trial number 4205.

Repeat whole blood donors with a ferritin level of 30 µg/L or less show functional iron depletion.

BACKGROUND: Whole blood donors are screened for iron depletion through hemoglobin measurement alone or in combination with ferritin. Ferritin measurement gives the advantage of earlier detection of iron depletion. In a previous study we identified a ferritin level of 30 µg/L or less as a possible indicator of suboptimal erythropoiesis. In this study, erythropoietic parameters were measured to determine if a ferritin level of 30 µg/L or less is indicative of iron-deficient erythropoiesis in repeat whole blood donors. STUDY DESIGN AND METHODS: Twenty-one healthy male repeat whole blood donors were divided into two groups according to their predonation ferritin values: 30 µg/L or less (low-ferritin group) and greater than 30 µg/L (normal-ferritin group). Ferritin and erythropoietic parameters were measured before whole blood donation and weekly in the 8 weeks after donation. RESULTS: A significantly lower value was found for hemoglobin, mean corpuscular volume (MCV), reticulocytes, and reticulocyte hemoglobin content on at least three of the nine time points in the low-ferritin group compared to the normal-ferritin group (p < 0.05). Of these parameters, MCV and reticulocyte hemoglobin content were significantly lower before donation as well as during all 8 weeks following donation (p < 0.05). CONCLUSION: Based on the lower values of the erythropoietic parameters in the low-ferritin group, it can be concluded that repeat whole blood donors with a ferritin value of 30 µg/L or less have iron-deficient erythropoiesis and therefore require a longer donation interval than the current 56 days.

Value of Prehospital Troponin Assessment in Suspected Non-ST-Elevation Acute Coronary Syndrome.

There is an increasing awareness that prehospital risk stratification in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) is important. The HEART score accurately identifies patients at low risk and is nowadays fully assessable outside the hospital after the development of point-of-care (POC) troponin tests. However, the added value of the troponin component to the prehospital HEART score has not yet been assessed. This is a prospective cohort study including 700 patients with suspected NSTE-ACS in which prehospital risk stratification using the HEART score was performed by paramedics. Low risk was defined as HEAR or HEART score ≦3. Troponin was measured by a POC troponin T Test device (Roche Cobas h232). Troponin <40 ng/l scored 0 point, troponin ≥40 ng/l scored 2 points. Primary end point was major adverse cardiac events (MACE) within 45 days after inclusion. Mean HEAR score was 4.5 ± 1.6, mean HEART score was 4.7 ± 1.7. Using the HEAR score, a total of 183 patients (26%) were stratified as low risk, whereas using the HEART score, 172 patients (25%) were stratified as low risk (p = 0.001). In both low-risk groups, there were no deaths within 45 days. Using HEAR, MACE occurred in 13 patients (7%) in the low-risk group, whereas using HEART, MACE occurred in 5 patients in the low-risk group (3%, p <0.001). The use of HEART (Area under the curve 0.74) obtained a higher predictive value compared to HEAR (Area under the curve 0.65, p <0.001) for MACE. In conclusion, in patients with suspected NSTE-ACS, the prehospital troponin component of the HEART score has important added predictive value.

Fast assessment and management of chest pain patients without ST-elevation in the pre-hospital gateway (FamouS Triage): ruling out a myocardial infarction at home with the modified HEART score.

BACKGROUND: The first study of the FamouS Triage project investigates the feasibility of ruling out a myocardial infarction in pre-hospital chest pain patients without electrocardiographic ST-segment elevation by using the modified HEART score at the patient's home, incorporating only a single highly sensitive troponin T measurement. METHODS: A venous blood sample was drawn in the ambulance from 1127 consecutive chest pain patients for measurement of the pre-hospital highly sensitive troponin T levels, in order to establish a pre-hospital HEART score (i.e. the modified HEART score) and evaluate the possibility of triage at the patient's home. The primary endpoint was the occurrence of a major adverse cardiac event (MACE) i.e. acute myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting or death within 30 days after initial presentation. RESULTS: Two hundred and six patients (18%) developed a MACE during 30 days of follow-up. Thirty-six per cent of the patients ( n=403) had a low modified HEART score (0-3 points) and none of them developed a MACE during follow-up. Forty-four per cent of the patients ( n=494) had an intermediate modified HEART score (4-6 points) and 18% of them developed a MACE. Twenty per cent of the patients ( n=230) had a high modified HEART score (7-10 points) of which 52% developed a MACE during follow-up. CONCLUSION: It seems feasible to rule out a myocardial infarction at home in chest pain patients without ST-segment elevation by using the modified HEART score. TRIAL ID: NTR4205. Dutch Trial Register [ http://www.trialregister.nl ]: trial number 4205.

Technical and clinical validation of the Greiner FC-Mix glycaemia tube.

BACKGROUND: Measurement of adequate glucose concentrations is complicated by in vitro breakdown of glucose due to glycolysis. Unlike the commonly used NaF-EDTA and NaF-oxalate phlebotomy tubes, citrated NaF-EDTA tubes are reported to directly and thereby completely inhibit glycolysis. Recently, Greiner introduced the Vacuette® FC-Mix NaF-EDTA-citrate tube, currently the only NaF-citrate tube without volume-disturbing liquid additions available on the European market. Here we present its potential as alternative for the laborious and therefore unfeasible conditions for glucose sampling as recommended by the World Health Organization (WHO). METHODS: The FC-Mix tube was tested against the WHO recommended method of optimal laboratory conditions, both in healthy volunteers and pregnant woman undergoing oral glucose tolerance test (oGTT) for screening of gestational diabetes mellitus (GDM). Glucose concentrations were measured after different incubation times (0-48 h) and temperatures (room temperature, 37 °C), both in uncentrifuged whole blood and centrifuged material. RESULTS: Deming regression analysis shows that glucose concentrations measured in the FC-Mix tube correlate to the WHO recommended method. Stability is maintained at room temperature for 48 h and at least 24 h at 37 °C. The use of the FC-Mix tube was also validated in screening for GDM and proved comparable to the WHO recommended method in diagnostic outcome. CONCLUSIONS: The new Greiner FC-Mix tube combines the easy handling of a routine tube with dry additive with the ability to immediately inhibit glycolysis as in the WHO method for optimal pre-analytical and analytical conditions and performs equally to those conditions when screening for GDM.

Whole Blood Donation Affects the Interpretation of Hemoglobin A1c.

INTRODUCTION: Several factors, including changed dynamics of erythrocyte formation and degradation, can influence the degree of hemoglobin A1c (HbA1c) formation thereby affecting its use in monitoring diabetes. This study determines the influence of whole blood donation on HbA1c in both non-diabetic blood donors and blood donors with type 2 diabetes. METHODS: In this observational study, 23 non-diabetic blood donors and 21 blood donors with type 2 diabetes donated 475 mL whole blood and were followed prospectively for nine weeks. Each week blood samples were collected and analyzed for changes in HbA1c using three secondary reference measurement procedures. RESULTS: Twelve non-diabetic blood donors (52.2%) and 10 (58.8%) blood donors with type 2 diabetes had a significant reduction in HbA1c following blood donation (reduction >-4.28%, P < 0.05). All non-diabetic blood donors with a normal ferritin concentration predonation had a significant reduction in HbA1c. In the non-diabetic group the maximum reduction was -11.9%, in the type 2 diabetes group -12.0%. When eligible to donate again, 52.2% of the non-diabetic blood donors and 41.2% of the blood donors with type 2 diabetes had HbA1c concentrations significantly lower compared to their predonation concentration (reduction >-4.28%, P < 0.05). CONCLUSION: Patients with type 2 diabetes contributing to whole blood donation programs can be at risk of falsely lowered HbA1c. This could lead to a wrong interpretation of their glycemic control by their general practitioner or internist.

Can the Afinion HbA1c Point-of-Care instrument be an alternative method for the Tosoh G8 in the case of Hb-Tacoma?

BACKGROUND: Hb-variant interference when reporting HbA1c has been an ongoing challenge since HbA1c was introduced to monitor patients with diabetes mellitus. Most Hb-variants show an abnormal chromatogram when cation-exchange HPLC is used for the determination of HbA1c. Unfortunately, the Tosoh G8 generates what appears to be normal chromatogram in the presence of Hb-Tacoma, yielding a falsely high HbA1c value. The primary aim of the study was to investigate if the Afinion HbA1c point-of-care (POC) instrument could be used as an alternative method for the Tosoh G8 when testing for HbA1c in the presence of Hb-Tacoma. METHODS: Whole blood samples were collected in K2EDTA tubes from individuals homozygous for HbA (n = 40) and heterozygous for Hb-Tacoma (n = 20). Samples were then immediately analyzed with the Afinion POC instrument. After analysis, aliquots of each sample were frozen at -80 °C. The frozen samples were shipped on dry ice to the European Reference Laboratory for Glycohemoglobin (ERL) and analyzed with three International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and National Glycohemoglobin Standardization Program (NGSP) Secondary Reference Measurement Procedures (SRMPs). The Premier Hb9210 was used as the reference method. RESULTS: When compared to the reference method, samples with Hb-Tacoma yielded mean relative differences of 31.8% on the Tosoh G8, 21.5% on the Roche Tina-quant Gen. 2 and 16.8% on the Afinion. CONCLUSIONS: The Afinion cannot be used as an alternative method for the Tosoh G8 when testing for HbA1c in the presence of Hb-Tacoma.