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1.

Introduction

Total 25-hydroxyvitamin D [25(OH)D] is the most reliable indicator of vitamin D status. In this study, we compared two automated immunoassay methods, the Abbott Architect 25-OH Vitamin D assay and the Roche Cobas Vitamin D total assay, with the liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Materials and methods

One hundred venous blood samples were randomly selected from routine vitamin D tests. Two of the serum aliquots were analyzed at the Abbott Architect i2000 and the Roche Cobas 6000’s module e601 in our laboratory within the same day. The other serum aliquots were analyzed at the LC-MS/MS in different laboratory. Passing-Bablok regression analysis and Bland-Altman plot were used to compare methods. Inter-rater agreement was analyzed using kappa (κ) analysis.

Results

The Roche assay showed acceptable agreement with the LC-MS/MS based on Passing-Bablok analysis (intercept: -5.23 nmol/L, 95% CI: -8.73 to 0.19; slope: 0.97, 95% CI: 0.77 to 1.15). The Abbott assay showed proportional (slope: 0.77, 95% CI: 0.67 to 0.85) and constant differences (intercept: 17.08 nmol/L; 95% CI: 12.98 to 21.39). A mean bias of 15.1% was observed for the Abbott and a mean bias of -14.1% was observed for the Roche based on the Bland-Altman plots. We found strong to nearly perfect agreement in vitamin D status between the immunoassays and LC-MS/MS. (κ: 0.83 for Abbott, κ: 0.93 for Roche) using kappa analysis.

Conclusion

Both immunoassays demonstrated acceptable performance, but the Roche Cobas assay demonstrated better performance than the Abbott Architect in the studied samples.Key words: 25-Hydroxyvitamin D, chromatography, immunoassay, methods, tandem mass spectrometry  相似文献   

2.
Errors in laboratory medicine occur in the preanalytical, analytical, and postanalytical phases. The errors are mostly detected in the preanalytical period. However, analytical errors are still an important source of error, despite their frequency is reduced significantly in years thanks to developments in laboratories. In this case, an analytical error was noticed during the verification of a patient’s results. The direct bilirubin of a 66-year-old male patient admitted to the emergency department was higher than the total bilirubin. The patient’s symptoms were fatigue and dyspnoea. Albumin and haemoglobin (Hb) concentrations of the patient were significantly low. After considering the patient’s demographics and laboratory results, the laboratory specialist suspected a paraproteinemia interference. Total protein was performed as a reflective test. The albumin/globulin ratio was reversed. Thereafter, serum protein electrophoresis (SPEP) and immunofixation electrophoresis (IFE) were performed as another reflective tests, respectively. SPEP and IFE results were in favour of monoclonal gammopathy. The patient was directed to a haematologist, underwent a bone marrow biopsy, and the result was reported as Waldenstrom’s macroglobulinemia with plasma cell differentiation expressing IgM-Kappa. The patient went on a chemotherapy protocol, and his condition has been improved in subsequent months. Detection of analytical errors is of great importance, like in our case, and may be used as a tool to identify patients who have not yet been diagnosed. The laboratory specialist must dominate the entire process of each test in the laboratory, be aware of the limitations of tests, and turn these disadvantages into advantages when necessary.  相似文献   

3.

Introduction

Gentamicin due to its low level of resistance and rapid bactericidal activity is commonly used to treat gram-negative bacteria. However, due to its toxic effects it needs to be monitored. To date, no interference has been reported with gentamicin assays.

Materials and methods

A patient with leg cellulitis and sepsis received a single dose of gentamicin and a sample was sent for gentamicin analysis. The sample showed high blank absorbance readings on Beckman DxC800 and DC800 analysers with various dilutions. A second sample was received and analysed on a Roche Cobas system to obtain a result. A third sample was received 107 hours later with the same results and this sample was then analysed neat and post ethanol precipitation on all the turbidimetric assays available on the DxC800 analyser.

Results

The high blank absorbance was observed upon addition of the reactive reagents due to protein precipitation. Although not obvious from the patient protein results, it was shown the presence of high IgM paraprotein, 18.9 g/L (reference range 0.4-2.3 g/L) was the cause of precipitation, giving high blank readings. Of all the other turbidimetric assays, only vancomicin and valproate showed similar high blank absorbance readings. To be able to provide more rapid results it was shown ethanol could be used as a precipitant of proteins in both calibrators and patient samples with acceptable recovery.

Conclusion

IgM paraprotein was identified as the cause of interference with the gentamicin, vancomicin and valproate assays. Protein interference in these assays can be overcome by precipitation with ethanol.Key words: turbidimetry, IgM, paraprotein, interference  相似文献   

4.
Despite ample sunshine, 50–90% Indian children have Vitamin D deficiency (VDD). This enigma of widespread VDD needs exploration especially among under-fives as physiological variations in Vitamin D Binding Protein (VDBP) levels could be potential confounders in the interpretation of total 25-hydroxyvitamin D [25(OH)D]. However, there is scarce information about relevance of VDBP levels in under-five age group. We therefore, explored association of VDBP levels among 1–5 year old children with VDD. Serum levels of 25(OH)D, VDBP, calcium, parathyroid hormone (PTH) and alkaline phosphatase were estimated in 210 apparently healthy children in the age group of 1–5 years. VDD was defined as serum 25(OH)D levels < 20 ng/ml as per the IOM classification. VDBP levels were classified as low if levels were < 168 μg/ml as per the kit. The prevalence of VDD was 79.5% (n = 167) and VDBP levels were low in 48.6% (n = 102) of children. 25(OH)D levels correlated positively with VDBP (r = 0.298, p = 0.0001). A significant number of children (52.7%) with VDD had low VDBP (p = 0.015). and despite adequate sun exposure, 43% of children showed VDD and 56.6% had low VDPB levels. The low VDBP levels largely explain low 25OHD levels without necessarily implying VDD. It may add a new dimension for better understanding of widespread VDD among under-five children. It thus, points towards the need for redefining cut offs and complete evaluation of vitamin D status among under-fives including VDBP.  相似文献   

5.
IntroductionMost laboratories routinely determine haemolysis, icterus and lipemia indices to identify lipemic samples and reject potentially affected results. Hypertriglyceridemia is the most common cause of lipemia and severe hypertriglyceridemia (≥ 11.3 mmol/L) is a major risk factor of acute pancreatitis.Laboratory analysisA 56-year-old woman attended the outpatient clinic for a follow-up visit 1 month after a kidney transplantation. Her immunosuppressive therapy consisted of corticosteroids, cyclosporine, and mycophenolic acid. The routine clinical chemistry sample was rejected due to extreme lipemia. The comment “extreme lipemic sample” was added on the report, but the requesting physician could not be reached. The Cobas 8000 gave a technical error (absorption > 3.3) for the HIL-indices (L-index: 38.6 mmol/L) which persisted after high-speed centrifugation. The patient was given a new appointment 2 days later. The new sample was also grossly lipemic and gave the same technical error (L-index: 35.9 mmol/L).What happenedThe second sample was manually diluted 20-fold after centrifugation to obtain a result for triglycerides within the measuring range (0.10–50.0 mmol/L). Triglycerides were 169.1 mmol/L, corresponding to very severe hypertriglyceridemia. This result was communicated to the nephrologist and the patient immediately recalled to the hospital. She received therapeutic plasma exchange the next day and did not develop acute pancreatitis.Main lessonThis case illustrates the delicate balance between avoiding the release of unreliable results due to lipemia and the risk of delayed diagnosis when results are rejected. Providing an estimate of the degree of hypertriglyceridemia might be preferable to rejecting the result.  相似文献   

6.
Vitamin D deficiency is highly prevalent in Indian children of northern, western and southern states. Serum 25 hydroxy cholecalferol (ng/ml) was analyzed in 310 children and adolescents of pediatric hospital of Kolkata, India. Serum calcium (mg/dl), phosphorous (mg/dl) and alkaline phosphatase (IU/L) data was obtained. Median 25(OH)D was 19 ng/ml. 19.2 % of population had serum 25(OH)D < 10 ng/ml (severe deficiency), 52.9 % had <20 ng/ml (deficiency), 24.5 % had 20–29 ng/ml (insufficiency) and 22.6 % had >30 ng/ml (optimum). Deficiency was highest in adolescents (86.1 %), followed by school children (61.0 %), lowest in pre-school children (41.6 %). 25(OH)D concentrations was lowest in winters (P = 0.002) and spring (P = 0.03) compared to summer. There was no correlation with calcium (P = 0.99), phosphorous (P = 0.23) and ALP (P = 0.63). There is high prevalence of vitamin D deficiency in children and adolescents of eastern India. Prevalence was lower in younger subjects. 25(OH)D did not correlate with bone mineral markers.  相似文献   

7.
IntroductionIntensive physical activity causes functional and metabolic changes in the athlete’s organism. The study aimed to verify the common national available reference intervals (RIs) for common inflammatory and screening coagulation tests in a population of healthy young female athletes.Materials and methodsOne hundred and twenty-one female athletes (age range: 16–34), from various sports disciplines (water polo, handball, volleyball, football, basketball), were included in the study. All participants completed the international physical activity short-form questionnaire. Blood samples were collected between 8–10 am, after an overnight fast, before any physical activity. Reference intervals were determined according to Clinical & Laboratory Standards Institute EP28-A3C Guidelines.ResultsCalculated RIs for white blood cell count (WBC), prothrombin time (PT), and activated partial thromboplastin time (APTT) ratio were in accordance with the common national RIs. Calculated RI for C-reactive protein (CRP) was lower (< 2.9 mg/L) than the proposed cut-off for a healthy population (< 5.0 mg/L). Reference interval for fibrinogen was higher (1.9–4.4 g/L), than the available RIs (1.8–3.5 g/L). D-dimer cut-off value was set at 852 µg/L fibrinogen equivalent units (FEU), higher than the proposed 500 µg/L FEU for venous thromboembolism (VTE) exclusion.ConclusionsThe applicability of the available RIs for WBC count, PT, and APTT-ratio was confirmed. However, RIs for CRP and fibrinogen differed significantly than the available common national RIs for the healthy non-athletes’ population. A higher cut-off for D-dimers should be extensively verified before implementation for VTE diagnosis exclusion in a group of healthy young female athletes.  相似文献   

8.
Clinicians request a large part of measurements of biological quantities that clinical laboratories perform for diagnostic, prognostic or diseases monitoring purposes. Thus, laboratories need to provide patient’s results as reliable as possible. Metrological concepts like measurement uncertainty and metrological traceability allow to know the accuracy of these results and guarantee their comparability over time and space. Such is the importance of these two parameters that the estimation of measurement uncertainty and the knowledge of metrological traceability is required for clinical laboratories accredited by ISO 15189:2012. Despite there are many publications or guidelines to estimate the measurement uncertainty in clinical laboratories, it is not entirely clear what information and which formulae they should use to calculate it. On the other hand, unfortunately, there are a small number of clinical laboratories that know and describe the metrological traceability of their results, even though they are aware of the lack of comparability that currently exists for patient’s results. Thus, to try to facilitate the task of clinical laboratories, this review aims to provide a proposal to estimate the measurement uncertainty. Also, different suggestions are shown to describe the metrological traceability. Measurement uncertainty estimation is partially based on the ISO/TS 20914:2019 guideline, and the metrological traceability described using the ISO 17511:2020. Different biological quantities routinely measured in clinical laboratories are used to exemplify the proposal and suggestions.  相似文献   

9.
IntroductionWe investigated the interference of haemolysis on ethanol testing carried out with the Synchron assay kit using an AU680 autoanalyser (Beckman Coulter, Brea, USA).Materials and methodsTwo tubes of plasma samples were collected from 20 volunteers. Mechanical haemolysis was performed in one tube, and no other intervention was performed in the other tube. After centrifugation, haemolysed and non-haemolysed samples were diluted to obtain samples with the desired free haemoglobin (Hb) values (0, 1, 2, 5, 10 g/L). A portion of these samples was then separated, and ethanol was added to the separated sample to obtain a concentration of 86.8 mmol/L ethanol. After that, these samples were diluted with ethanol-free samples with the same Hb concentration to obtain samples containing 43.4, 21.7, and 10.9 mmol/L. Each group was divided into 20 equal parts, and an ethanol test was carried out. The coefficient of variation (CV), bias, and total error (TE) values were calculated.ResultsThe TE values of haemolysis-free samples were approximately 2-5%, and the TE values of haemolysed samples were approximately 10-18%. The bias values of haemolysed samples ranged from nearly - 6.2 to - 15.7%.ConclusionsHaemolysis led to negative interference in all samples. However, based on the 25% allowable total error value specified for ethanol in the Clinical Laboratory Improvement Amendments (CLIA 88) criteria, the TE values did not exceed 25%. Consequently, ethanol concentration can be measured in samples containing free Hb up to 10 g/L.  相似文献   

10.
Extensive data from animal and human studies indicate a role of vitamin D in erythropoiesis. Iron and vitamin D deficiencies are implicated with adverse health effects in children even if they are asymptomatic. The potential relationship between the two remains poorly understood. A cross-sectional study was performed in the period from 1st May 2012 through 30th April 2013 and subjects were classified into vitamin D deficiency (VDD), vitamin D insufficiency (VDI) and vitamin D sufficiency (VDS) groups according to their 25(OH) D levels. A total of 263 children were included in the analysis. Anaemia was present in 66 % of 25(OH) D deficient subjects compared with 35 % in vitamin D sufficient individuals (p < 0.0001). The association of breast feeding and development of VDD was also significant (p < 0.05). Serum levels of 25(OH) D were found lower in female sex and if the analysis was performed in the winter/spring season. Physicians should therefore assess vitamin D levels in all anaemic children and ensure adequate supplementation to prevent deficiencies.  相似文献   

11.
Low back pain is very disabling and dispiriting because of the physical impediment it causes and its psychological effects. Innumerable factors have been implicated in its etiology. In spite of improvements in diagnostic modalities, a considerable number of such cases fall in the ambiguous zone of unknown etiology or ‘idiopathic.’Early diagnosis of low back pain will allow effective prevention and treatment to be offered. This study was conducted to assess the contribution of vitamin D levels and other biochemical factors to chronic low back pain in such cases. All patients attending the orthopedics OPD for low back pain in whom a precise anatomical cause could not be localized, were prospectively enrolled in this study. We measured serum levels of glucose, calcium, phosphorus, uric acid, rheumatoid factor, C reactive protein, alkaline phosphatase, total protein, albumin and 25 (OH) D concentrations in 200 cases and 200 control samples. The patients showed significantly lower vitamin D levels compared to controls with p value < 0.0001. The maximum number of low back pain patients were in the age group of 31–50 years (42 %).The average BMI was 23.27 ± 5.17 kg/sq m, 73 % of total patient population were females and 27 % were known case of type 2 diabetes mellitus. Calcium, alkaline phosphatase, was positively correlated with vitamin D and glucose showed a negative correlation with vitamin D in the patient population. The problem of low back pain provides a challenge to health care providers. The problem in developing countries is compounded by ignorance to report for early treatment and occupational compulsions in rural areas and sedentary lifestyle in urban youth. The authors strongly recommend early frequent screening for vitamin D along with glucose, protein, albumin, calcium, phosphorus, CRP as part of general health checkup for non-specific body pain, especially low back pain.  相似文献   

12.
We aimed to estimate metabolic bone profile in a large cohort of healthy, adult Indian population to generate reference standards of serum calcium, phosphate and alkaline phosphatase (ALP), 25 (OH) Vitamin D and iPTH, and also to find out the prevalence of Vitamin D deficiency in healthy population. Apparently healthy people in the age group of 20–80 years, residing in the union territory of Chandigarh were chosen. Fasting samples for serum calcium, phosphate, albumin, alkaline phosphatase (ALP), 25 (OH) D and iPTH were collected and were processed on the same day. We recruited 930 healthy subjects from different subsectors of Chandigarh. Final analysis was done for 915 subjects. Out of this, 530 (58%) were women and 385 (42%) were men. The study participants were divided into two groups, less than and more than 50 years for the men and pre and post-menopausal for the women. The serum calcium, phosphate, ALP and iPTH were significantly higher in the post-menopausal women compared to the pre-menopausal women. The median plasma 25 (OH) D in men and women was 12.5 ng/mL and 14.3 ng/mL, respectively. 25 (OH) D deficiency was seen in 65.4% of individuals. 25 (OH) D levels co-related negatively with iPTH levels (r = − 0.4, p < 0.0001), and showed an increasing trend with age. We have thus presented metabolic bone profile of healthy, adult north Indian population. These reference values can be used for diagnosis and monitoring of various MBDs. Vitamin D deficiency is still rampant in our population in spite of increasing awareness.  相似文献   

13.

Introduction

Glycolysis affects glucose determination in vitro. The placement of sample tubes in ice-water slurry with plasma separation within 30 minutes is recommended, or alternatively the use of a glycolysis inhibitor. The aim of our two-steps study was to evaluate which Terumo tube is best for glucose determination in routine clinical setting.

Materials and methods

In the first study, blood from 100 volunteers was collected into lithium heparin (LH), NaF/Na heparin (FH) and NaF/citrate buffer/Na2EDTA (FC-Mixture) tubes. LH sample was treated as recommended and considered as reference, while FH and FC-Mixture samples were aliquoted, maintained at room temperature (RT) for 1, 2 and 4 hours; centrifuged and plasma analysed in triplicate. In the second study, samples from 375 volunteers were collected in LH, FH and FC-Mixture tubes and held at RT before centrifugation from 10 to 340 minutes, depending on each laboratory practice. Samples were analysed in one analytical run.

Results

In the first study, FH glucose concentrations were 5.15 ± 0.66 mmol/L, 5.05 ± 0.65 mmol/L and 5.00 ± 0.65 mmol/L (P < 0.001) in tubes stored at RT for 1, 2 and 4 hours, respectively. Mean biases in all time points exceeded the analytical goal for desirable bias based on biological variation criteria. FC-Mixture glucose concentrations were 5.48 ± 0.65 mmol/L, 5.46 ± 0.6 mmol/L and 5.46 ± 0.64 mmol/L in tubes stored at RT for 1, 2 and 4 hours, respectively. Mean biases for FC-Mixture glucose in all time points reached optimal analytical goals. In the second study, the biases for LH and FH glucose compared to reference FC-Mixture glucose exceeded the preset analytical goals, regardless of the blood collection to centrifugation time interval.

Conclusions

FC-mixture tubes glucose concentrations were preserved up to 4h storage at RT. We confirmed that NaF alone does not allow immediate glycolysis inhibition in real life pre-centrifugation storage conditions (up to 340 minutes). FC-Mixture should be used exclusively for glucose determination in laboratories unable to implement the recommended blood samples’ treatment.Key words: glucose, pre-analytical phase, sodium fluoride, citrate acidification, stability  相似文献   

14.

Introduction

Extremely high glucose concentrations have been shown to interfere with creatinine assays especially with Jaffe method in peritoneal dialysate. Because diabetes is the fastest growing chronic disease in the world, laboratories study with varying glucose concentrations. We investigated whether different levels of glucose spiked in serum interfere with 21 routine chemistry and thyroid assays at glucose concentrations between 17-51 mmol/L.

Materials and methods

Baseline (group I) serum pool with glucose concentration of 5.55 (5.44-5.61) mmol/L was prepared from patient sera. Spiking with 20% dextrose solution, sample groups were obtained with glucose concentrations: 17.09, 34.52, and 50.95 mmol/L (group II, III, IV, respectively). Total of 21 biochemistry analytes and thyroid tests were studied on Abbott c8000 and i2000sr with commercial reagents. Bias from baseline value was checked statistically and clinically.

Results

Creatinine increased significantly by 8.74%, 31.66%, 55.31% at groups II, III, IV, respectively with P values of < 0.001. At the median glucose concentration of 50.95 mmol/L, calcium, albumin, chloride and FT4 biased significantly clinically (-0.85%, 1.63%, 0.65%, 7.4% with P values 0.138, 0.214, 0.004, < 0.001, respectively). Remaining assays were free of interference.

Conclusion

Among the numerous biochemical parameters studied, only a few parameters are affected by dramatically increased glucose concentration. The creatinine measurements obtained in human sera with the Jaffe alkaline method at high glucose concentrations should be interpreted with caution. Other tests that were affected with extremely high glucose concentrations were calcium, albumin, chloride and FT4, hence results should be taken into consideration in patients with poor diabetic control.Key words: assay interference, glucose interference, preanalytical phase, creatinine, Jaffe kinetic assay, thyroid function tests  相似文献   

15.

Introduction:

Studies about vitamin D [25(OH)D] stability in plasma are limited and preanalytical variables such as tube type may affect results. We aimed to evaluate effect of storage conditions, sample type and some preanalytical variables on vitamin D concentration.

Materials and methods:

Blood samples from 15 healthy subjects were centrifuged at different temperatures and stored under different conditions. Serum and plasma 25(OH)D difference, effect of centrifugation temperature and common storage conditions were investigated.

Results:

There was no difference between serum and plasma vitamin D concentration. Centrifugation temperature had no impact on vitamin D concentration. 25(OH)D is stable under common storage conditions: 4 hours at room temperature, 24 hours at 2–8 °C, 7 days at −20 °C, 3 months at −80 °C.

Conclusion:

Vitamin D does not require any special storage conditions and refrigeration. Both serum and plasma can be used for measurement.  相似文献   

16.

Introduction

Hemolysis can occur during sample collection, handling and transport. It is more frequent when the non-laboratory staff performs sampling. The aim of this study was to assess nurses’ knowledge on the causes of hemolysis and consequential impact on the laboratory tests results. Additionally, the differences in knowledge, related to work experience, professional degree and previous education about hemolysis were explored.

Materials and methods

An anonymus survey, containing 11 questions on demographics, causes of hemolysis, its impact on biochemical parameters and nurses’ attitude towards additional education in preanalytics, was conducted in four Croatian hospitals. The answers were compared by Chi-squared and Fischer exact test.

Results

In total, 562 survey results were collected. Majority of nurses declared familiarity with the term “hemolysis” (99.6%). There were 77% of correct answers regarding questions about the causes of hemolysis, but only 50% when it comes to questions about interference in biochemical tests. The percentage of correct answers about causes was significantly lower (P = 0.029) among more experienced nurses, and higher (P = 0.027) in those with higher professional degree, while influence of previous education was not significant. Also, higher percentage of correct answers about interferences was encountered in nurses with longer work experience (P = 0.039). More than 70% of nurses declared that additional education about preanalytical factors would be beneficial.

Conclusion

Croatian nurses are familiar with the definition of hemolysis, but a lack of knowledge about causes and influence on laboratory test results is evident. Nurses are eager to improve their knowledge in this field of preanalytical phase.Key words: hemolysis, nurses, survey, preanalytical phase  相似文献   

17.
A 50 year old male was admitted in our hospital with anemia and impaired renal function. He was subsequently found to have extremely elevated serum phosphate level (24 mg/dL, reference interval: 2.5–4.5 mg/dL) with normal serum calcium when assayed on a Beckman Coulter AU 480® analyser. Clinico-biochemical discrepancy led to the suspicion of spurious hyperphosphatemia. Serum total protein was grossly elevated with gross reversal of albumin to globulin ratio. Serum electrophoresis revealed a large M band and was confirmed as Ig G-Kappa type on immunofixation. Subsequently a bone marrow aspiration biopsy confirmed the diagnosis of multiple myeloma. The patient serum was then reassayed for phosphate on a Vitros® 250 Dry Chemistry platform and the result was within normal reference interval. Paraproteinemias are a common cause of analytical interference in clinical biochemistry laboratories and as multilayered film technology platforms like Vitros® assay most routine analytes on a protein free filtrate they are unaffected by paraprotein interference. Clinically discordant patient results should always be interpreted keeping such interferences in mind.  相似文献   

18.

Introduction:

Additional nucleotide substitutions in the 3′-untranslated region of prothrombin gene could explain some thrombotic events and also adverse pregnancy outcomes. We describe the first case of a homozygous 20209C>T mutation as the cause of deep vein thrombosis in a Spanish patient.

Case and methods:

The 56-year-old male patient with a partial tear of the Achilles tendon developed calf (tibial) deep vein thrombosis after immobilization and was treated with an anticoagulant. To determine if the deep vein thrombosis was of genetic origin, a peripheral blood DNA sample was analysed for the presence of the three most frequent mutations associated with thrombotic events: factor V Leiden (1691G>A), prothrombin (20210G>A) and methylene tetrahydrofolate reductase (677C>T). The presence or absence of the normal allele of prothrombin could not be determined using the PTH-FV-MTHFR StripAssay (Vienna Lab).

Results:

Comprehensive analysis showed that the patient had a variant interfering with the polymerase chain reaction product, we sequenced the entire prothrombin gene and found that the patient had a homozygous C>T mutation at position 20209; this interfered with the polymerase chain reaction product, which needs a C at this position to be able to bind to the wild-type probe present in the test strip.

Conclusion:

The homozygous 20209C>T mutation and the presence of the mutation 677C>T in heterozygosity explained the patient’s deep vein thrombosis because the combination of mutations would increase the risk of thrombosis. Suitable genetic counselling should be provided to the patient and first-degree relatives as it important to detect prothrombin gene variants that could increase risk for thrombotic events.  相似文献   

19.

Introduction

Measurements of blood ethanol concentrations must be accurate and reliable. The most important factors affecting blood ethanol stability are temperature and storage time. In this study, we aimed to compare ethanol stability in plasma samples at -20 °C for the different storage periods.

Materials and methods

Blood samples were collected from intoxicated drivers (N = 80) and initial plasma ethanol concentrations were measured immediately. Plasma samples were then stored at -20 °C and re-assessed after 2, 3, 4, or 5 months of storage. Differences between the initial and stored ethanol concentrations in each group (N = 20) were analyzed using Wilcoxon matched-pairs test. The deviation from the initial concentration was calculated and compared with Clinical Laboratory Improvement Amendments (CLIA’88) Proficiency Testing Limits. Relationships between the initial concentrations and deviations from initial concentrations were analyzed by Spearman’s correlation analysis. For all statistical tests, differences with P values of less than 0.05 were considered statistically significant.

Results

Statistically significant differences were observed between the initial and poststorage ethanol concentrations in the overall sample group (P < 0.001). However, for the individual storage duration groups, analytically significant decreases were observed only for samples stored for 5 months, deviations from the initial concentrations exceeded the allowable total error (TEa). Ethanol decreases in the other groups did not exceed the TEa.

Conclusion

According to our results, plasma ethanol samples can be kept at -20 °C for up to 3-4 months until re-analysis. However, each laboratory should also establish its own work-flow rules and criterion for reliable ethanol measurement in forensic cases.Key words: preanalytical phase, ethanol, stability, storage temperature  相似文献   

20.
Determination of ammonia level in blood is important, especially in the diagnosis of hepatic disorders. An indigenously purified enzyme was used in the standardisation of the assay. The assay is a two reagent system, requires five minutes for completion and can be performed at temperature between 25–27°C. Performance of the assay was assessed by linearity, imprecision, functional sensitivity and interference studies. Lyophilised reagent I and reagent II were found stable for at least one year. The plasma level of ammonia for the controls was 13.7±7.3 μMol/L, whereas for subjects of hepatic disorders, it was 69.1±32.4 μMol/L (P<0.001). The functional sensitivity was between 2–1000 μMol/L. Within-run coefficient of variation was between 1.1–2.0% and between-run coefficient of variation was between 1.9–3.7%. The mean recovery after dilution was 99.6%. The present method can estimate ammonia up to 1000 μMol/L without dilution of sample. Assay time of five minute may be shortened to one minute. This method is suited for routine clinical use in treatment of hepatic disorders.  相似文献   

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