Effects of Storage Temperature and Time on Stability of Serum Tacrolimus and Cyclosporine A Levels in Whole Blood by LC-MS/MS

Tacrolimus and cyclosporine A are immunosuppressant drugs with narrow therapeutic windows. The aim of this study was to investigate the stability of tacrolimus and cyclosporin A levels in whole blood samples under different storage conditions. Whole blood samples were obtained from 15 patients receiving tacrolimus and 15 patients receiving cyclosporine A. Samples were immediately analyzed and then stored at different conditions (room temperature (24°C−26°C) for 24 hours, +4°C for 24 and 48 hours, and −20°C for one month) and then analyzed again. For tacrolimus, there was a significant difference between samples analyzed immediately and those kept 24 hours at room temperature (P=0.005) (percent change 32.89%). However, there were no significant differences between the other groups. For cyclosporine A, there was a significant difference between samples analyzed immediately and those kept 24 hours (P=0.003) (percent change 19.47%) and 48 hours (P=0.002) (percent change 15.38%) at +4°C and those kept 24 hours at room temperature (P=0.011) (percent change 9.71%). Samples of tacrolimus should be analyzed immediately or stored at either +4°C or −20°C, while samples of cyclosporine A should be analyzed immediately or stored at −20°C

Evidence-based laboratory: determining the insufficiency level of vitamin D

WOS: 000379432200006Aim: There is lack of studies on the relationship between parathyroid hormone and vitamin D levels for defining deficiency and insufficiency of vitamin D in adults living in Turkey. Therefore, we searched for threshold value of 25-hydroxyvitamin D concentration below which parathyroid hormone levels would significantly increase. Methods: Between the dates of 01.03.2015 and 01.06.2015, the results of patients older than 18 years were scanned from the laboratory information system. Eight hundred three patients, whose simultaneously analyzed serum levels of calcium, inorganic phosphate, creatinine and intact parathyroid hormone were within the reference ranges and 25-hydroxyvitamin D was <50 ng/mL, were included in the study. Results: There was a significant difference in intact parathyroid hormone levels between subjects with 25-hydroxyvitamin D levels of 15-10 and those with 10-5 ng/mL (p=0.05). A significant increase in intact parathyroid hormone levels (p=0.01) was found to start with a 25-hydroxyvitamin D level below 22 ng/mL within the range of 30 to 10 ng/mL. Consequently, we determined the first 25-hydroxyvitamin D threshold in which intact parathyroid hormone levels significantly increase to be 22 ng/mL and the second threshold as 10 ng/mL. Conclusion: Evaluation of parathyroid hormone which has a major role in the regulation of vitamin D should be done to define and diagnose vitamin D deficiency and insufficiency correctly

Diagnostic pitfall of carryover: in automatic urine analyzers

WOS: 000393197500013Objective: We aimed to find out whether there is significant carryover effect which causes false-positive hematuria on red blood cells (RBCs) in automatic urine chemistry (DIRUI H-800) and sediment (DIRUI FUS-200) analyzers. Methods: Twenty-four samples with gross hematuria selected as containing high RBC concentration and forty-eight samples which had both negative result in dipstick and 0/hpf in microscopic examination selected as containing low RBC concentration. Carryover% was calculated via the formula [carryover% = 100 x (b(1) - b(2))/(a(2) - b(2))]. Carryover effect within results was analyzed with Wilcoxon test. Results: Carryover% was very high (67%) in urine chemistry analyzer. Carryover% of urine sediment analyzer was found 0.4% whilst false-positive hematuria percentage was 87.5% for the first samples came after gross hematuria and 6.6% for the second samples. The first samples analyzed after gross hematuria had significantly higher (p 3/hpf) is low. To prevent carryover in both urine analyzers; washing procedures should be revised and the diagnostic effect of carryover should also be taken into account by biochemists

Roles of c-reactive protein and procalcitonin in empirical treatment approach to the bacterial sepsis agent

WOS: 000412463200005Objective: The primary aim of our study was to investigate the usefulness of serum C-reactive protein (CRP) and procalcitonin (PCT) levels in the differential diagnosis of causative gram-positive (Gram+) or gram-negative (Gram-) bacteria in patients with sepsis to facilitate decisions concerning the initial choice of an empiric antibiotic regimen. Methods: Between February 2014 and February 2016, 47 patients who had sepsis diagnosed on the basis of positive blood cultures and clinical examination results were retrospectively enrolled. Serum CRP and PCT levels of 15 gram+ and 32 gram-bacterial sepsis groups were compared using the Mann-Whitney U test. The correlation between CRP and PCT levels was calculated using the Spearman's test. Results: Among patients with bacterial sepsis, the median CRP level was 91.42 mg/L and the median PCT level was 0.46 ng/mL. There were no significant difference in CRP and PCT levels between the gram+ and gram-sepsis groups (p=0.98 and p=0.21, respectively). There was good correlation between the CRP and PCT levels (r=0.64, p<0.001). Conclusion: Considering the changes and the status of proinflammatory/anti-inflammatory responses in the pathogenesis of sepsis, we believe that CRP and PCT levels alone are insufficient for predicting the type of causative bacteria in sepsis

Common MEFV gene mutations in children with FMF in Diyarbakır, Turkey

Familial Mediterranean Fever (FMF) is an autosomal recessive disease that clinically characterized by periodic abdominal pain, fever and arthralgia. Wide variety of mutations have been described in MEFV gene which is known to be responsible from FMF. In present study, 12 MEFV mutations [E148Q, P369S, F479L, M680I (G/C), M680I (G/A), I692del, M694V, M694I, K695R, V726A, A744S, R761H] have been screened. DNA samples were obtained from a total of 332 children, who were clinically suspected as FMF. Mutation analyses of MEFV gene were carried out with reverse hybridization method. In 113 children (mean age 11.5 years), mutations have been detected. In 60 children E148Q (4 homozygous), in 19 M694V (4 homozygous), in 16 P369S (none), and in 13 children V726A (none homozygous) mutations were detected. Among Familial Mediterranean Fever -suspected 332 children 104 fulfilled diagnostic criteria for FMF and detected MEFV gene mutations with decreasing frequency were; E148Q (30.8%), M694V (18.3%), P369S (10.6%), V726A (8.6%), A744S (2.9%), R761H (2.9%), M694I (1.9%), K695R (1.9%) and I692del (1.0%), respectively. No mutation was detected in 15 (14.4%) FMF children while, two different MEFV mutations were detected together in 13 (12.5%) patients and these patients were accepted as a compound heterozygous. In conclusion, in our patients E148Q mutation was found higher than M694V mutation that has been detected commonly in patients with FMF. The difference may result from demographic features or used methods

Standardization and performance evaluation of manual measurement method for paraoxonase activity

Objectives: We hypothesised that using the traditionallaboratory methods for preparing the kit with chemicalsmay represent sufficient analytic performance with commercialkits, because of the fresh reagents and cost effective.We aimed to apply the paraoxonase (PON1) studyprocedure to the autoanalyser and evaluate the analyticperformance of the study.Methods: Thirty five healthy individuals were includedin the study. A total of 100 mL serum pool was createdafter centrifugation of venous blood samples. To assessthe intra-assay variations of PON1 enzyme activities 20samples and for inter-assay variations 30 samples wereprepared from the serum pool and PON1 enzyme activitieswere studied. As well as, 30 samples were studied toevaluate the correlation between the commercial kit andthe manual prepared kit from chemicals.Results: In this study, the mean, standard deviation (SD),percent coefficient of variation (% CV) values of PON1enzyme activities for intra-assay (72.70 U / L, 0.43, 0.59)and inter-assay (74.24 U / L, 3.00, 4.04) were determined.The correlation coefficient between the manual methodand the commercial kit were r = 0.92 and r2 = 0.84.Conclusion: The results of manual kit were showed goodanalytical performance with commercial kit. Therefore,the serum pool which was partially standardized in thisstudy was portionized for using as an internal quality controlserum for future studies in our laboratory. However,the use of standardized control sera, is considered to bemore reliable in routine laboratories.Key words: Paraoxonase, standardization, internal qualitycontro

Logical Basis of Cerebrospinal Fluid and Serum S-100B Protein Measurement in Pregnant Women to Detect any Possible Cerebral Damage

OBJECTIVE: The aim of the study was to consider logical basis of serum and cerebrospinal fluid (CSF) S100B measurement in pregnant females to detect any cerebral damage. STUDY DESIGN: CSF and serum samples from 14 pregnant patients (age: 20-34 years) were obtained during spinal anesthetic procedure of cesarean section. The serum samples from 9 non-pregnant patients (22–36 years) without an organic brain disease were used as normative data. S-100B levels in serum and CSF samples were measured with electrochemiluminescence immunoassay method. The CSF and blood serum levels of pregnants and blood serum levels of pregnant and nonpregnant females were compared using Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: Serum S100B protein levels of pregnant females were significantly higher [0.66±0.06 ng/ml] than those observed in [0.06±0.00 ng/ml] nonpregnant females (p<.0001). There was a significant difference between the S100B protein levels of CSF and blood serum (p<0.05) in pregnant females. However the correlation between these two levels was insignificant (p=0.473). CSF S100B levels of pregnant subjcets were significantly higher than the serum levels of pregnant and nonpregnant subjects (p<0.0001). DISCUSSION: These results prove that the maternal serum and CSF S100B protein levels are independently related to each other in pregnancy