Comparative Analysis of Whole Blood Ionised Calcium, Lactate and Chloride Concentrations by Gem Premier 3000 and Edan I15 Vet and the Effect of Parity and Postpartum Blood Collection Time on Blood Calcium Status in Holstein With and Without Subclinical Hypocalcemia - Part 1

Lactating Holstein (n=125) were enrolled randomly for the coccygeal whole blood analysis by blood gas devices GEM Premier 3000 (GEM) and Edan i15 Vet (EDAN) between calving to postpartum day 3 (G1) and postpartum day 4 to 27 (G2). Blood pH, ionised calcium (ICA7.4) and lactate analysis were significantly correlated between GEM and EDAN (r=0.86, 0.94, 0.87 respectively). The bias for ICA7.4, lactate and pH analysis was -0.054, -0.344 mmol/L and +0.009 respectively. ICA7.4 was correlated negatively with parity and chloride, but positively with lactate. The averages of ICA7.4 and serum total calcium (TC) was significantly lower in G1 than G2. Chloride and lactate were significantly higher in G1 than G2. Subclinical hypocalcemia prevalence (SCH) (serum TC<2.15 mmol/L, as reference) was 52.9% in G1 and 21.1% in G2. Cows with SCH had frequently over 50% ICA7.4/TC ratio. Sensitivity analysis provided a sensitivity of 57.4% for ICA7.4 cut-points of 1.02 (GEM) and 1.05 (EDAN) mmol/L to detect SCH based on reference serum TC. Primiparous (PRP) with and without SCH in G1 had significantly higher ICA7.4 than multiparous (MUL). Cows with SCH had significantly higher chloride in G1 than G2. MUL had significantly higher lactate and chloride in G1 than G2. Conclusively, ICA7.4 and pH analysis between GEM and EDAN were correlated well with acceptable biases, but high differences occurred in lactate analysis. MUL was at risk in G1 due to lower ICA7.4 and TC over PRP. Higher ICA7.4 of PRP can reduce the risk and frequency of clinical hypocalcemia. SCH correlated negatively with Cl concentration in G1, but not lactate.

Diagnostic Performance of the BHBCheck β-Hydroxybutyrate Meter for Hyperketonemia in Indian Cows and Buffaloes

The objective of the study was to evaluate diagnostic performance of the electronic hand-held BHBCheck meter (PortaCheck, Inc, USA; BHM) to determine blood, plasma and serum β-hydroxybutyrate (BHB) against serum BHB determined using reference laboratory method of Randox D-3 Hydroxybutyrate Ranbut assay (RSM) in Indian cows and buffaloes. Blood samples were collected by puncturing coccygeal vessels for determining serum and plasma BHB using BHM and serum BHB using RSM from 217 cows (Gir breed; median 42 DIM and 3rd lactation) and 223 buffaloes (non-descript; median 39 DIM and 3rd lactation) from nearby herds. Cow-side blood BHB were determined with BHM. The Pearson’s correlation between blood (0.988; 0.987), plasma (0.985; 0.983) and serum (0.985; 0.983) BHB determined using the BHM and serum BHB determined with the RSM were significant. Bland-Altman plot demonstrated an excellent agreement between blood, plasma and serum BHB determined with BHM, against the serum BHB determined with RSM. For hyperketonemia with reference serum BHB cut-off values ≥ 1.2 and 1.4 mmol/L determined with RSM; recorded optimized BHB thresholds, sensitivity and specificity for blood (≥ 0.9 to 1.0 mmol/L; 91 to 95% and 88 to 98%) plasma (≥ 0.9 to 1.0 mmol/L; 91 and 100%) and serum (≥ 0.9 to 1.0 mmol/L; 92 to 100% and 85 to 94%) with BHM in cows and buffaloes. In conclusion, BHB determined with BHM demonstrated an excellent correlation, agreement and test characteristics with BHB determined with RSM, hence, can accurately determine blood, plasma and serum BHB in cows and buffaloes.

Changing the paradigm of bicarbonate (HCO3−) hemodialysis prescription in Portugal: a 24-month prospective study

Background Metabolic acidosis is common in hemodialysis (HD) patients. The KDOQI guidelines therapeutic goal is pre-dialysis HCO3− ≥ 22 mmol/L. The aim of the study was to evaluate an individualized HCO3− hemodialysis prescription as a preventing factor of metabolic changes. Methods Twenty-four-month prospective study of patients on online high-flux hemodiafiltration. Every 3 months, HCO3− blood levels were analyzed and hemodialysis HCO3− was changed using the following rules: HCO3− > 30 mmol/L: reduce 4 mmol/L HCO3− HCO3− ≥ 25 mmol/L: reduce 2 mmol/L HCO3− 20 mmol/L < HCO3− < 25 mmol/L: no change HCO3− ≤ 20 mmol/L: increase 2 mmol/L HCO3− HCO3− < 18 mmol/L: increase 4 mmol/L HCO3− Data collected comprised demographic information, renal disease etiology, comorbidities, HD treatment information, and lab results. Statistical analysis was performed using SPSS. Results Thirty-one patients were enrolled and completed the follow-up period. At baseline, average serum pH was 7.38 ± 0.06, serum HCO3− 25.92 ± 1.82 mmol/L, and every patient had a 32 mmol/L dialytic HCO3− prescription. At time point 9, average serum HCO3− was 23.87 ± 1.93 mmol/L and 58% of the patients had a dialytic HCO3− prescription of 28 mmol/L. Serum HCO3− differed with statistical significance during time and approached the reference serum HCO3− (23 mmol/L) that we have defined as ideal. Through time, the HCO3− prescription deviated more from the 32 mmol/L initial prescription that was defined as standard. Conclusions Our findings suggest that the standard HCO3− prescription of 32 mmol/L should be rethought, as an individualized HCO3− prescription could be beneficial for the patient.

Preliminary evaluation of a candidate international reference for Epstein–Barr virus capsid antigen immunoglobulin A in China

Background: The detection of the Epstein–Barr capsid antigen (VCA) immunoglobulin A (IgA) is widely used inthe diagnosis of nasopharyngeal carcinoma (NPC),but a reference standard for evaluating the presence of VCA-IgA isnot yet available. Therefore, a reference standard is urgently needed for a uniform and quantitative detection of VCA-IgA.Methods: A mixed reference serum from three NPC patients diluted with healthy subject serum was made as a potential first international standard for VCA-IgA. VCA-IgA was detected in twenty NPC patients by four ELISA kits and two chemiluminescent immunoassays kits using the reference as a calibration curve. The performance of these six kits was evaluated, and the quantitative results were compared. Results: Our results showed a good linearity of the reference in different kits. Without reference, the difference of the total coefficient of variation (from 3.98% to 43.11%) and Within-run coefficient of variation (from 2.47% to 19.66%) was large in the 6 kits. The positive and negative coincidence rate between the 6 kits and indirect immunofluorescence for NPC diagnosis was 75% overall agreement, but a difference among the six kits was found, ranging from 55% to 90%. The concentration of VCA-IgA in the 20 NPC samples led in the division into three categories such as negative, low, or medium/high positive, but these concentrations were significantly different within these three categories depending on the kit used of the 6 considered. However,a good correlation (R2=0.986) was observed between Antu and Beier ELISA kits.Conclusions: The reference serum mightbe used as a reference standard for a better comparison of the results from different kits/laboratories.However, the quantitative results of some kits are still inconsistent due to the diversity of VCA antigens.

Preliminary evaluation of the candidate international reference for Epstein–Barr virus capsid antigen immunoglobulin A in China

Background: Epstein–Barr capsid antigen (VCA) immunoglobulin A (IgA) detection is widely used for nasopharyngeal carcinoma (NPC), but reference standard for VCA-IgA has not yet been determined. For uniform and quantitative detection of VCA- IgA, reference standard is in urgent need. Methods: A mixed reference serum from three patients with NPC diluted with healthy subjects serum was made as a possible first international standard for VCA-IgA. Four ELISA kits and two chemiluminescent immunoassays(CLIA) kits were used to detected VCA-IgA in twenty NPC patients using the reference as a calibration curve. The performance of six kits were evaluated, and the quantitative results were compared. Results: Our results shown the reference has good linearity in different kits. Without reference, the difference of total CV (from 3.98% to 43.11%) and Within-run CV(from 2.47% to 19.66%) was large in 6 kits. The positive and negative coincidence rate between 6 kits and IFA for NPC diagnosis was 75% overall agreement, but there was a difference among the six kits ranged from 55%-90%. Concentration of 20 NPC samples divided into three sample categories was shown significant difference in a few subgroup of 6 methods. But a good correlation (R2=986) was observed between Antu and Beier ELISA kits. Conclusions: The reference serum may be used as a reference standard and better compared results from different methods/laboratories. However, due to the diversity of VCA antigens, the quantitative results of some kits are still inconsistent.

Reference intervals of the magnesium in the healthy individuals, residents of Astrakhan

Objective: to establish reference serum magnesium intervals in healthy individuals, residing in Astrakhan.Materials and methods: the investigated group was formed from 120 men and 120 women healthy residents of Astrakhan aged from 21 to 50 years (average age 37,6 ± 0,9). Th e study of calcium was carried out on an automatic biochemical analyzer “Cobas 311 c” (Roche Diagnostic, Germany) by photometric method.Results: the reference intervals for the magnesium in healthy men and women aged from 21 to 50 years, residing in Astrakhan is 0,72 – 0,99 mmol/L.Conclusion: the reference range of total magnesium, established by us, can be used in laboratories of Astrakhan, as it was developed taking into account domestic and foreign recommendations for selection donors for research and ensuring the quality of laboratory research at all stages.

Evaluation of different immunoassays for the quantitative detection of Epstein–Barr virus capsid antigen immunoglobulin A using a candidate reference

Background As Epstein–Barr capsid antigen (VCA) immunoglobulin A (IgA) detection is widely used for nasopharyngeal carcinoma (NPC),many immunoassays are available for VCA- IgA detection. Methods We evaluated the performance of different immunoassays for the quantitative detection of VCA-IgA. Twenty NPC patients were detected VCA-IgA by four ELISA kits and twochemiluminescent immunoassays(CLIA) kits using the reference as a calibration curve. The performance of six kits were evaluated, and the quantitative results were compared. Results Our results shown the reference has good linearity in different kits. Without reference, the difference of total CV (from 3.98% to 43.11%) and Within-run CV(from 2.47% to 19.66%) was large in 6 kits. The positive and negative coincidence rate between 6 kits and IFA for NPC diagnosis was 75% overall agreement, but there was a difference among the six kits ranged from 55%-90%. Concentration of samplesdivided into three categories was shown significant difference in certain subgroup of 6 kits. Almost all assays gave a correlation coefficient lower than 0.80, except for Antu and Beier kit and Tarcine kit and New Industries kit. Conclusions The reference serum may be used as a reference standard and better compared results from different methods/laboratories.Despite the use of our reference, the quantitative results of each kit are still quite different.We should try to unify the diversity between different antigens to promote the development of VCA-related research in the further.

Assignment of Serotype-Specific IgG1, IgG2, and IgA Weight-Based Antibody Units to the Human Pneumococcal Standard Reference Serum, 007sp

ABSTRACTIn 2011, the human pneumococcal standard reference serum, 007sp, was established as a replacement for the previous standard, lot 89SF, supplies of which were dwindling. The pneumococcal reference serum is used primarily in the standardized pneumococcal enzyme-linked immunosorbent assay (World Health Organization reference enzyme-linked immunosorbent assay) but has also been used in functional assays. Serotype-specific IgG values for 24 pneumococcal capsular serotypes have previously been assigned to 007sp by bridging to the original values derived for lot 89SF. In this study, by bridging to existing values in lot 89SF, we assign weight-based serotype-specific IgA, IgG1, and IgG2 to 007sp for 11 pneumococcal capsular serotypes (1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F), as well as serotype 19A-specific IgA. Concentrations for serotype-specific IgA, IgG1, and IgG2 present in 007sp were comparable to those previously assigned to lot 89SF. In addition, the concentration of serotype-specific IgG1 plus IgG2 assigned to 007sp significantly correlated to previously assigned 007sp IgG values. The accuracy of antibody assignments to 007sp from lot 89SF was assessed by comparing the concentration of serotype-specific IgA, IgG1, and IgG2 in 16 unknown samples using both 007sp and lot 89SF as the standard. Interpolated values for the unknown samples were highly correlated with averageR2values of 0.9729, 0.9951, and 0.9933 for IgA, IgG1, and IgG2, respectively, for all serotypes demonstrating the precise nature assignments to 007sp made in this study. Nonparallelism between 007sp and lot 89SF has precluded the derivation of serotype-specific IgM values.IMPORTANCEA well-characterized antibody standard is an indispensable reagent for use in assays designed to measure antibodies with precision and where assays between laboratories need to be comparable. The human pneumococcal standard reference serum, lot 89SF, greatly facilitated the standardization of enzyme-linked immunosorbent assay methodologies during a critical period when the first pneumococcal polysaccharide-conjugate vaccines were being evaluated for licensure. Due to dwindling supplies of lot 89SF, a new reference standard, 007sp, was produced in 2011. Understanding the isotype and subclass composition of either natural or vaccine induced responses to pathogens has assumed increasing importance. In this study, we have assigned IgA, IgG1, and IgG2 values to pneumococcal serotypes 1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F by bridging to existing values in lot 89SF.