Impact of managing affected results in haemolysed samples of an infant-maternity hospital using an unconventional approach.

BACKGROUND: The management of affected results in haemolysed samples (HS) is debated. In an infant-maternity setting, for reporting interfered test results, we provided the result itself, the degree of haemolysis (as free haemoglobin concentration), and a warning recommending sample recollection. We investigated the impact of this approach on sample quality and clinicians' decision-making. METHODS: Free haemoglobin was measured on Beckman Coulter AU680 as haemolytic index. We estimated the total HS number, the clinical wards more affected by HS, the most interfered analytes, and the retesting rate of interfered tests, by comparing data from Apr-Dec 2017, the period just after the introduction of the new policy, vs. Apr-Dec 2018. RESULTS: One year after the new report introduction, a significant HS decrease (5.8% vs. 7.8%, P < 0.001) was detected, together with a reduction of the frequency by which haemolysis affected results. The most affected wards, i.e., Paediatric and Neonatal Intensive Care Units, showed an improvement in sample quality (HS rate, 30.6% to 16.1%, P < 0.001, and 25.2% to 20.9%, P = 0.048, respectively). We noted a significant decrease in retesting after an alerted result for aspartate aminotransferase, magnesium, potassium, conjugated bilirubin, and lactate dehydrogenase. CONCLUSIONS: Our approach led to a HS decrease, suggesting that the provided report could be a driving force for improvement of phlebotomy quality, also helping clinicians in deciding if retesting is essential or not.

kEDTA Sample Contamination: A Reappraisal.

BACKGROUND: Potassium EDTA (kEDTA) contamination of serum samples is common, causing spurious hyperkalemia, hypozincemia, and hypocalcemia that if unrecognized may adversely affect patient care. Gross kEDTA contamination is easy to detect, but identification of spurious electrolytes due to small amounts of contamination requires measurement of serum EDTA. We validated an EDTA assay on the Abbott Architect and reassessed its value in identifying kEDTA contamination and in studying mechanisms for contamination. METHODS: Within- and between-batch imprecision, linearity, recovery, interference, and carryover were assessed. Serum supplemented with k2EDTA plasma, to mimic sample contamination, was used to study its effect on potassium, calcium, zinc, magnesium, and alkaline phosphatase. Our current laboratory protocol for identification of kEDTA contamination, based on measurement of serum calcium, was compared to that of EDTA measurement. RESULTS: The EDTA assay displayed acceptable performance characteristics. Hemoglobin was a positive interferent. EDTA was detectable in serum contaminated with 1% (v:v) k2EDTA plasma. An increase in serum potassium of 0.54 mmol/L (11.9%) was observed at a measured EDTA concentration of 0.19 mmol/L, equivalent to 3.2% (v:v) contamination. At this EDTA concentration reductions were also observed in zinc (71%), calcium (1%), alkaline phosphatase (ALP) (4%), and magnesium (2.4%). The serum EDTA assay detected contamination in 31/106 patient samples with hyperkalemia (potassium ≥6.0mmol/L), 20 of which were undetected by the current laboratory protocol. CONCLUSIONS: The EDTA assay displayed acceptable performance, with the ability to reliably measure EDTA at low concentrations. Only a small amount of kEDTA causes significant spurious hyperkalemia and is only reliably detected with EDTA measurement.

The right blood collection tube for therapeutic drug monitoring and toxicology screening procedures: Standard tubes, gel or mechanical separator?

Stability data of toxics or drugs in gel-based or mechanical separation blood collection tubes are lacking, especially for therapeutic drug monitoring and clinical toxicology procedures. According to ISO 15189 accreditation standard, laboratories need to master the entire preanalytical process including the stability of analytes in a specific tube. Here we explored the impact of BD PST™ II and Barricor™ separator tubes on the stability of 167 therapeutic compounds and common drugs of abuse in plasma samples using LC-MS/MS. Forty drugs were significantly affected by the use of PST™ II tubes, including antidepressants (11/26), neuroleptics (9/13), cardiovascular drugs (5/26), anxiolytics and hypnotics (4/25) and some drugs of abuse (5/26). Six compounds exhibited significant reduction by the mechanical Barricor™ tubes. Ten drugs exhibited low (<85%) but non-significant recoveries due to inter-assay variability. Besides, a logP > 3.3 was determined as a cut-off value to predict a potential lack of stability in PST™ II gel tubes with an 86.4% sensitivity and a 61.4% specificity. As a consequence, determination of drugs with a logP > 3.3 should be carried out with caution in plasma samples withdrawn on PST™ II. The study showed the Barricor™ and non-gel tubes cause less drug interference and are recommended for the drugs studied.

Comparison of Barricor™ vs. lithium heparin tubes for selected routine biochemical analytes and evaluation of post centrifugation stability.

INTRODUCTION: Obtaining suitable results unaffected by pre- or postanalytical phases is pivotal for clinical chemistry service. We aimed comparison and stability of nine biochemical analytes after centrifugation using Barricor™ plasma tubes with mechanical separator vs standard Vacutainer® lithium heparin tubes. MATERIALS AND METHODS: We collected samples on six healthy volunteers and nine patients from intensive care units into 6 mL plastic Vacutainer® lithium heparin tubes and 5.5 mL plastic Barricor™ plasma tubes. All tubes were centrifuged within 30 minutes after venipuncture. First, we compared results of nine biochemical analytes from lithium heparin tubes with Barricor™ tubes for each analyte using Passing-Bablok and Bland-Altman analyses. Second, we calculated the difference of analyte concentrations between baseline and time intervals in tubes stored at + 4 °C. Based on the total change limit we calculated the maximum allowable concentrations percentage change from baseline. RESULTS: The majority of correlation coefficients were close to 0.99 indicating good correlation in the working range. Bland-Altman analyses showed an acceptable concordance for all analytes. In consequence, the Barricor™ tube might be an alternative to regular lithium heparin tube. Stability with this new generation tube is improved for eight analytes (except for aspartate aminotransferase) in comparison with regular lithium heparin tubes. CONCLUSIONS: By using Barricor™ tubes and prompt centrifugation, supplemental analysis or re-analysis for eight analytes including alanine aminotransferase, alkaline phosphatase, C-reactive protein, high sensitivity troponin T, lactate dehydrogenase, NT-pro BNP, potassium and sodium could be performed within 72 h of specimen collection.

Assessment of Cardiac Troponin I Responses in Nonhuman Primates during Restraint, Blood Collection, and Dosing in Preclinical Safety Studies.

Limited information has been published on the use of cardiac troponin I (cTnI) as a biomarker of cardiac injury in monkeys. The purpose of these studies was to characterize the cTnI response seen in cynomolgus macaques during routine dosing and blood collection procedures typically used in preclinical safety studies and to better understand the pathogenesis of this response. We measured cTnI using two different methods, the Siemens Immulite cTnI assay and the more sensitive Siemens Troponin I-Ultra assay. We were able to demonstrate that after oral, subcutaneous, or intravenous dosing of common vehicles, as well as serial chair restraint for venipuncture blood collection, that minimal to mild transient increases in cTnI could be detected in monkeys with both assays. cTnI values typically peaked at 2, 3, 4, or 6 hr after sham dosing and returned to baseline at 22 or 24 hr. In addition, marked increases in heart rate (HR) and blood pressure (BP) occurred in monkeys during the restraint procedures, which likely initiated the cTnI release in these animals. Monkeys that were very well acclimated to the chairing procedures and had vascular access ports for blood sampling did not have marked increases in HRs and BP or increases in cTnI.

[Postcolostral immunoglobulin G (IgG) levels in newborn piglets using three different ELISA detection systems]. / Untersuchungen zur postkolostralen Immun-globulin-G-Versorgung neugeborener Saugferkel mittels unterschiedlicher ELISA-Nachweissysteme.

UNLABELLED: Objective of the study was to evaluate whether the Colostrum Quality Counter (CQC), a new test method for immunoglobulin G (IgG) levels in newborn piglets, is easy to handle and provides comparable results to established testing regimes. MATERIAL AND METHODS: Blood samples from 219 piglets from four different farms were tested for their IgG-concentrations using three different ELISA tests. Furthermore, double samples from 30 piglets were taken from both the anterior vena cava and from the tail to determine whether the collection site affects the results. The three tests used were the Colostrum Quality Counter (CQC; FarmulaONE, NL-Best), the internal IgG-ELISA from our laboratory (MUC) and a commercially-available IgG-ELISA (NAT; NatuTec, Frankfurt/Main, Germany). RESULTS: MUC and NAT showed a higher correlation to each other than to the CQC when referring to the individual results per single piglet. The results from the CQC were higher and the standard deviation was significantly greater. The sampling site had no significant effect on the IgG concentrations measured. CLINICAL RELEVANCE: The CQC is a straightforward and simple test, being very convenient for sampling a large number of piglets. CQC results were inhomogeneous with some unusually high IgG-concentrations. MUC and NAT provided comparable results to one another and the IgG-concentrations showed a good correlation.

Right or wrong sample received for coagulation testing? Tentative algorithms for detection of an incorrect type of sample.

Inappropriate blood collection potentially comprises the major pre-analytical problem for coagulation testing. Inappropriate samples are most difficult to detect when received as secondary aliquots, common for referred tests. This study aimed to identify a simple, quick and inexpensive process to help laboratories distinguish the type of sample, should there be suspicion of inappropriate collection. Samples from 15 patients [selected on the basis that four different primary tubes were available: serum, citrated plasma, ethylene diamine tetraacetic acid (EDTA) plasma, lithium-heparin plasma], were tested for common electrolytes that might substantially differ according to the type of sample. In citrated plasma, potassium, chloride, calcium and magnesium were significantly decreased compared with serum and lithium-heparin plasma, while sodium was markedly increased. In EDTA plasma, sodium and chloride were significantly decreased compared with both serum and lithium-heparin plasma, potassium was always >14 mmol/l, whereas magnesium and calcium were virtually undetectable. These data allowed development of two algorithms for differential identification of citrated plasma vs. other samples with 100% sensitivity and specificity, the former based on the sequential measurement of potassium, calcium and sodium, the latter on potassium and sodium. These simple assays can supplement classical coagulation test methods to identify most inappropriate blood collections and validate sample rejection.

Frequency of isolation and antimicrobial susceptibility pattern of bacterial isolates from blood culture, Gondar University teaching hospital, Northwest Ethiopia.

BACKGROUND: Bacterial bloodstream infections cause substantial morbidity and mortality, with up to one-quarter of affected patients dying as a result of their infection. Up-to-date information on blood culture isolates and their antimicrobial susceptibility pattern is very important as guide for immediate prescription of antimicrobial agents and monitoring of emergence of drug resistant strains. OBJECTIVE: To determine the frequency of blood culture isolation and antimicrobial susceptibility pattern of isolates in Gondar University teaching hospital. METHODS: This was retrospective analysis of records of blood culture results for febrile patients seen at Gondar University teaching hospital, bacteriology section from March 2001 to April 2005. RESULTS: During the four years period, blood cultures were done for a total of 472 febrile patients. Among these, 233 (49.4%) were females and 239 (50.6%) were males. The median age was 20.5 years (age range of 2 hours to 78 years). Out of these, total of 114 bacterial strains were isolated with culture positivity rate of 24.2%. Coagulase-negative Staphylococci (CoNS) were isolated with the highest frequency in 38 (33.3%), followed by Staphylococcus aureus in 34 (29.8%), Salmonella species other than Salmonella typhi in 12 (10.5%), Klebsiella species in 10 (8.8%), Streptococcus pneumoniae in 6 (5.3%), Salmonella typhi in 4 (3.5%), Enterobacter species in 3 (2.6%), Escherichia coli in 2 (1.7%). The gram positive and gram negative bacteria constituted 80 (70.2%) and 34 (29.8%) of the culture isolates, respectively. Culture positivity rates vary as for neonates, 63% (17 out of 27);followed by 25.6% (36 out of 141) in children and 20% (61 out of 304) in adults. The isolates especially gram negative bacteria showed multiple drug resistance, to Ampicillin and penicillin. However, ciprofloxacin is fairly effective against both gram negative and gram positive isolates. CONCLUSION: An effective documented data may serve as a guide for initial empirical treatment of bloodstream infections but in view of these findings the presented data is only imperative to do large-scale prospective and quantitative studies. More importantly, an ongoing surveillance for antimicrobial susceptibility is of the essence to enhance efforts to identify resistance and attempt to limit its spread.

A new plastic collection tube made of polyethylene terephtalate is suitable for monitoring traditional anticoagulant therapy (oral anticoagulant, unfractionated heparin, and low molecular weight heparin).

To improve the safety of blood collection, plastic tubes have been developed but various interactions with the coagulation system and/or antithrombotic drugs were reported with the first generation of such tubes. The aim of this multicentre study was to compare hemostasis test results measured in evacuated plastic tubes made of polyethylene terephtalate (VenoSafe, Terumo Europe) and in siliconized glass tubes containing the same citrate concentration (0.129 M). In addition, the impact of aging of the plastic tube was investigated by collecting blood samples in tubes at 8 months and at 1 month before expiry. Blood was drawn in 3 centres from untreated patients (n=269), patients on oral anticoagulant treatment (OAT, n=221), and patients treated with either unfractionated heparin (UFH, n=73) or a low molecular weight derivative (LMWH, n=48). Prothrombin time (PT) or INR, activated partial thromboplastin time (APTT) and anti-FXa activity were locally performed, when applicable. In untreated patients and in patients on OAT, PT and APTT values were found statistically shorter (p<0.05) when evaluated in plastic tubes than in glass tubes, except when PT was evaluated using a human thromboplastin. Surprisingly, significantly longer APTT and higher anti-FXa activities were obtained when blood from patients on UFH was drawn in plastic than in glass tubes. However, none of the differences had any clinical relevance (Bland-Altman analysis). In patients on anticoagulant treatment, there was no effect of aging of the plastic tubes. These results suggest that the plastic tube VenoSafe is suitable for coagulation testing both in untreated subjects and more interestingly in patients on traditional anticoagulant therapy during the whole shelf life indicated by the manufacturer.

Newborn blood spot screening.

The U.K. Newborn Screening Programme Centre (UKNSPC) launched the first UK-wide standards and policies for newborn blood spot screening, together with a national pre-screening information leaflet for parents in December 2004. These standards are included in a document pack that has been sent recently to all heads of midwifery and local screening coordinators. This article describes the standards and policies, as well as the supporting guidelines, that are relevant to midwifery.

[Legal aspects of preparation and handling of concentrated red cells derived from placental blood in Germany]. / Juristische Aspekte bei der Herstellung und Verwendung von Plazentablut-Erythrozytenkonzentraten in Deutschland.

Legal aspects of collection, preparation and storage of autologous red cells derived from cord blood according to German law are presented and discussed.

Reference individuals, blood collection, treatment of samples and descriptive data from the questionnaire in the Nordic Reference Interval Project 2000.

The rules for recruitment of reference individuals, inclusion and preparation of individuals, blood collection, treatment of samples (and control materials) and analysis at the 102 medical laboratories attending the Nordic Reference Interval Project (NORIP) are given as well as the rules for central exclusion of reference individuals. The individuals (18-91-year-olds) should be evenly distributed on age and gender groups. The 3002 reference individuals who contributed at least one reference value to the finally suggested reference intervals were characterized using the information in the questionnaire. Gender, age and country are the main entries in the tables. Other variables in the cross-tables or figure are height, weight, body mass index, ethnic origin, heredity for diabetes, chronic disease, oestrogens or oral contraceptives, other medication, hard physical activity, previous blood donations, smoking habits, use of alcohol, hours since last meal and time of blood collection (hour, day of week, month, year). The Danes had the highest alcohol consumption and the Icelanders had the highest body mass index. The information in this article may interest potential users of the Nordic Reference Interval Project bio-bank and database (NOBIDA) in which serum, Li-heparin plasma and EDTA buffy coat from the mentioned individuals are stored below -80 degrees C.

Autologous red cells derived from cord blood: collection, preparation, storage and quality controls with optimal additive storage medium (Sag-mannitol).

To investigate whether packed red cells (PRCs) prepared from autologous cord blood-packed red cells (AC-PRCs) could be used as an alternative for homologous-packed red cells (H-PRCs), we developed a system to collect and prepare AC-PRCs and determined standard storage parameters during 35 days of storage in extended storage medium (Sag-mannitol). We collected and fractionated cord blood from 390 newborns. The amount and quality of the AC-PRCs were analysed. The bacterial contamination rate was 1.84%. Twelve AC-PRCs were stored for 35 days, and standard laboratory parameters were measured at day 1 and day 35. The initial laboratory parameters of the AC-PRCs were similar to the parameters of the H-PRCs. After 35 days, the AC-PRCs displayed an increased haemolysis rate compared to H-PRCs (1.1 versus 0.2%) and also a significant decreased adenosine triphosphate value (1.2 versus 2.3 micromol L(-1)). Haemoglobin, haematocrit and pH were comparable in both groups. AC-PRCs meet the quality criteria for H-PRCs after 35 days. Utilizing a closed collection system for cord blood and an extended storage medium will increase safety and quality and facilitate the routine transfusion of autologous red cells derived from cord blood.

Screening for congenital hypothyroidism in the Islamic Republic of Iran: strategies, obstacles and future perspectives.

The operational feasibility of a congenital hypothyroidism (CH) screening programme was assessed. Cord blood spot specimens were collected at seven Teheran hospitals and within the Damavand District health network. Cord thyroid-stimulating hormone (TSH) levels > or = 20 mU/L were recalled and levothyroxine (L-T4) therapy was started immediately after diagnosis of CH. Of 20,107 acceptable specimens, 22 neonates had CH (1:914 births). The recall rate was 1.3%. Screening coverage was 90% of live births. Of all cord samples, only 0.2% were unacceptable either because of delay in transportation or improper specimen collection. Median ages at the time of diagnosis and starting treatment were 12 and 8 days respectively. Screening for CH is feasible and a national screening programme is a necessity.

Arginine inhibits hemostasis activation.

BACKGROUND: The diagnosis and the therapy of in vivo hemostasis activation is of great clinical importance. Artefactual changes of the hemostasis (i.e., coagulation or fibrinolysis) in vitro have to be prevented. Usual in vitro anticoagulation by sodium citrate does not fully inhibit coagulation--or fibrinolysis--activation. Therefore, there is need for a simple physiologic inhibitor of hemostasis activation both in diagnosis and therapy of hemostasis activation. METHODS: Whole blood clotting time (WBCT), prothrombin time (PT), activated partial thromboplastin time (APTT), in vitro bleeding test closure time (IVBT-CT), and whole blood aggregometry (WBA) were determined in normal human blood or plasma, supplemented with increasing concentrations of L-arginine or guanidine. RESULTS: Arginine in concentrations of 5-100 mM inhibited the WBCT, PT, APTT, IVBT-CT, and WBA. Arginine (50 mM) resulted in a two-fold prolongation of WBCT, PT, or IVBT-CT (the anti-epinephrine action is superior to the anti-ADP action), a four-fold prolongation of APTT or a 60% inhibition of WBA. CONCLUSION: L-Arginine (or guanidine) inhibited the activation of hemostasis. Arginine might be used as hemostasis stabilizer both in the diagnosis and therapy of hemostasis activation. The usage of arginine as an in vitro hemostasis inhibitor might be indicated in the diagnosis of hemostasis activation, as occurring in pharmacological thrombolysis or disseminated intravascular coagulation (DIC). The storage of blood or blood products might be improved by arginine stabilization. The amino acid (and nitric oxide precursor) L-arginine could be an interesting new pharmacologic agent to inhibit a pathologic hemostasis activation.

Effects of different concentrations of anticoagulant on the in vitro characteristics of autologous whole blood.

BACKGROUND: Routinely, 450 mL of blood is collected into 63 mL of CPDA-1, for a final anticoagulant:blood ratio of approximately 1:7 in a whole-blood autologous unit. If less than 300 mL of blood is to be collected, the AABB standards suggest that there should be a proportionate decrease in anticoagulant. Data from an autologous blood program showed a range in volume from 92 mL to 667 mL per bag, which reflects an anticoagulant:blood ratio of 2:1 to 1:10. STUDY DESIGN AND METHODS: To determine the effects of these ratios on the in vitro function of RBCs at various anticoagulant ratios, blood was collected into different amounts of anticoagulant, and various measurements were made during storage. RESULTS: The number of RBCs and the MCV remained constant over time, regardless of the anticoagulant dilution used. Plasma free Hb increased with time with all dilutions. At a 1:2 ratio, it rose from 734 mg per L on Day 1 to 1805 mg per L on Day 35, and at 1:8, it was 355 mg per L for Day 1 and 854 mg per L on Day 35. Plasma sodium decreased and the potassium increased over time with all dilutions. From Day 1 to Day 35, there was a nine-fold increase in potassium at both the 1:2 and 1:8 dilutions (2.4 to 22.9 mmol/L, 3.2 to 29.6 mmol/L, respectively). The LDH increased over time and the pH decreased in all of the dilutions. Osmotic fragility remained constant at the 1:8 dilution but decreased at all of the other dilutions with storage, with 44-percent fragility on Day 35 at the 1:2 ratio. The WBC and platelet counts decreased consistently over time. Overall, 1 percent of the autologous units were below the cutoff volume of 300 mL at which an adjustment of the anticoagulant volume is required. CONCLUSION: Plasma Hb and plasma potassium concentrations are considerably higher in low-volume units, which indicates that deviation from standard collection procedures is deleterious to RBCs.

A survey of autologous blood collection and transfusion in Japan in 1997.

BACKGROUND: In spite of the fact that autologous blood is safest for a patient to receive, it is not generally appreciated that adverse reactions during donation and transfusion may occur. This study was conducted to assess the state and the risk of autologous blood transfusion in Japan in 1997. STUDY DESIGN AND METHODS: Results of a nation-wide questionnaire-based survey are presented. The questionnaire assessed the number of autologous blood donations, donation procedures, and the adverse reactions associated with donation, preservation, recombination erythropoietin administration and transfusion. RESULTS: Between November 1996 and October 1997, 10,697,000 ml (or 53,485 units, 200 ml = 1 unit) prestorage blood donation were made by 14,200 patients (averages; 1.9 donations/patient, 753 ml/patient, 398 ml/donation). Of these, 87% were transfused to the patients and the remainder were discarded. Using hemodilution and blood salvage intra- or postoperatively some 2,540,000 ml of blood was collected and > 70% of patient-donors received such blood. Adverse reactions were observed with 1.6% (428/26,905) of donations including 6 angina and 2 asthma attacks. There were 63 (0.2%) problems with 28,705 donations and 117 (0.5%) errors/problems reported for 24,929 units transfused; the most frequent problems were clotting on the units and breakage of the bags during storage. Hypotension using hemodilution (3.7%), coagulation (0.9%) or bacterial contamination (0.4%) using salvage were often observed. A 10-20 ml volume of autologous fresh-frozen plasma was transfused to the wrong recipient. CONCLUSION: Autologous blood transfusion accounts for at least 1.1% (2.8% estimated) of the red cell supply in Japan. Errors and adverse reactions are not infrequent in autologous blood programmes. By introducing systematic safety policies, we will be able to make autologous blood transfusion safer.