Respective Reference Intervals Research Articles

Comparison of 2 Serum Free Light Chain Assays with Creatinine Normal and Abnormal Populations Demonstrates the Need for Standardization.

The objective of this study was to compare The Binding Site's Freelite on Optilite and Diazyme's Kappa/Lambda free light chains (K/L FLC) on Abbott Architect c8000 with healthy and renal insufficient populations and to evaluate their respective reference intervals for serum free light chains (sFLCs). Two hundred sixty serum samples were measured for creatinine and sFLCs by both assays and a subset by immunofixation electrophoresis. Verification of manufacturer-defined reference intervals was assessed. Kappa free light chains (KFLC) showed excellent correlation of 0.998 R2 with a slope of 0.73. For Lambda free light chains (LFLC), an acceptable correlation of 0.953 R2 was found with a slope of 1.50 as well as a skewness-based difference with a -12.70 intercept. Healthy estimated glomerular filtration rate (eGFR) ≥60 reference interval verification of central 95% could not be confirmed for either Freelite or Diazyme although LFLC was much closer than KFLC for both assays with Freelite KFLC recovering only 37% of values within reference interval claims. The K/L FLC ratio did not meet 100% claim for both Freelite (91%) and Diazyme (95%) among those with eGFR ≥60. Samples with eGFR ≤59 had increasingly higher levels of KFLC and LFLC for both assays. When comparing worsening eGFR status, Freelite recovered increasingly higher ratios while Diazyme recovered increasingly lower ratios. Healthy reference intervals could not be verified for either Freelite or Diazyme. Renal reference intervals for Freelite are currently warranted while they are not recommended for Diazyme. The differences between these 2 assays can be minimized by standardization efforts such as recalibration.

Reference change values of FIB-4

When comparing two analytical results for the same analyte, the clinicians may benefit from knowing the reference change values (RCVs) of the analyte. For Fibrosis-4 Index (FIB-4), a noninvasive test used for assessing the risk of liver fibrosis, no RCVs have been published for non-cirrhotic individuals. Therefore, we estimated RCVs for adults, using retrospectively collected data from outpatients with AST, ALT, and thrombocytes within the respective reference intervals. FIB-4 was calculated as (age × AST)/(thrombocytes × ALT0.5). From two FIB-4 values in each patient we calculated the RCVs parametrically and non-parametrically. For both methods, we estimated the limits of the central 90% of the distribution of the ratio between the second and the first measurement. We obtained data on 599 outpatients with two blood tests taken 3 - 972 (median 258) days apart. The RCVs were 0.72 − 1.40 and 0.72 − 1.43, respectively, using the parametric and non-parametric methods. The 5 and 95 percentiles were not statistically significantly associated with sex, age, level of analyte, or the time between the measurements. The within-subject biological variation of FIB-4 was estimated to be 13.9%. Conclusion: In 90% of the patients the ratio between the second and the first FIB-4 result was approximately 0.7 − 1.4.

Comparison of plasma total carbon dioxide and standard hydrogen carbonate in a hospital laboratory setting.

Studies comparing venous total carbon dioxide (tCO2) and standard hydrogen carbonate (HCO3-(P,st)) has shown diverse results, and it is debatable whether these two parameters can be used interchangeably for workup of acid-base disorders in a hospital setting. All patients with an HCO3-(P,st) requisition from any department at Odense University Hospital between 11th May 2021 and 1st June 2021 had tCO2 and HCO3-(P,st) analysed simultaneously. TCO2 was measured on Cobas® 8000, c702 module, while HCO3-(P,st) was calculated based on measurements on ABL835 Flex. From 1210 patients, mean (standard deviation (SD)) was 22.9 (3.7) mmol/L for tCO2 and 22.5 (2.9) mmol/L for HCO3-(P,st). TCO2 range was 10.1-42.3mmol/L and 11.7-41.4mmol/L for HCO3-(P,st). Linear regression showed that tCO2 (mmol/L) = -2.90 + 1.15 × HCO3-(P,st) (mmol/L) with R2 = 0.81. Bias (mean (SD) difference) between tCO2 and HCO3-(P,st)) was 0.4 (1.7) mmol/L with a -5.0-9.6mmol/L range. Limits of agreement was -2.90-3.70mmol/L. Comparison of classification within, above or below reference interval for tCO2 and HCO3-(P,st) showed that 984 samples (81%) retained their classification. Only one sample (0.1%) would be severely misclassified (outside the respective reference intervals) if HCO3-(P,st) was considered the gold standard. Of the samples investigated, 46.1% had a mean difference between tCO2 and HCO3-(P,st) of 0-1mmol/L and 30.3% had 1.1-2.0mmol/L. Our results indicate that venous tCO2 and venous HCO3-(P,st) can be used interchangeably in a hospital setting for workup of acid-base disorders.

Dietary 25-hydroxyvitamin D3 effects on vitamin D status, plasma metabolites and urine mineral excretion in adult cats.

The study aimed to evaluate the safety and effectiveness of vitamin D supplementation with dietary 25-hydroxyvitamin D3 (25[OH]D3) in adult cats. Three levels of dietary 25(OH)D3 concentrations (4.9, 8.4, 11.8 µg/kg as fed) were received by five adult cats for 9 weeks, each in a randomized complete block design. Effects were determined on plasma or serum concentrations of 25(OH)D3, 24,25-dihydroxyvitamin D3, calcitriol, parathyroid hormone, ionized calcium, urinary excretions of phosphorus, calcium and magnesium, and clinical hematology and chemistry panels. The lowest concentration of dietary 25(OH)D3 supported elevation of vitamin D status, with no adverse effects. Supplementation of 8.4 µg/kg 25(OH)D3 had significant effects on the urinary magnesium: creatinine ratio. Increasing supplementation up to 11.8 µg/kg 25(OH)D3 had significant effects on plasma concentrations of calcium and magnesium, and vitamin D metabolites. Dietary supplementation with approximately 5.0 µg/kg of 25(OH)D3 or the ingested equivalence of 0.09 µg of 25(OH)D3 per metabolic body weight (kg0.67) is a safe, potent and effective means for raising vitamin D status in cats. A higher dose with approximately 11.8 µg/kg of 25(OH)D3 resulted in elevation in C-3 epimers of 25(OH)D3 and slight elevation in plasma magnesium and calcium concentrations above their respective reference intervals.

Serial analysis of blood biomarker concentrations in dogs with pneumonia, septic peritonitis, and pyometra.

BackgroundProlonged antimicrobial drug (AMD) treatment is associated with antimicrobial resistance development. Biomarker measurement may aid treatment decision‐making.ObjectivesInvestigate temporal changes in blood biomarker concentrations in dogs undergoing treatment for pulmonary and intra‐abdominal infections; compare time to biomarker concentration normalization with duration of clinician‐directed AMD treatment.AnimalsForty‐two client‐owned dogs with pneumonia (n = 22), septic peritonitis (n = 10), or pyometra (n = 10).MethodsPlasma concentrations of C‐reactive protein (CRP), serum amyloid A (SAA), haptoglobin, procalcitonin, nucleosomes, cell‐free DNA (cfDNA), high‐mobility group box‐1 (HMGB1), CC‐motif chemokine ligand‐2 (CCL2), CXC‐motif chemokine ligand‐8 (CXCL8), and keratinocyte chemoattractant‐like (KC‐Like) were quantitated in samples collected on days 1, 3, 7, 14, 28, and 60. Treatment was directed by clinicians blinded to biomarker concentrations.ResultsConcentrations of CCL2, CRP, and KC‐Like were maximal on D1, concentrations of SAA, cfDNA, HMGB1, and nucleosomes were maximal on D3 and haptoglobin concentrations were maximal on D7. These maximal concentrations were significantly different from those on D60. Concentrations of CRP and SAA decreased by 80% from peak and into respective reference intervals before AMDs were discontinued. For CRP, the median (interquartile range [IQR]) times to 20% peak and normal were 7 (6‐9) and 7 (6‐12) days, respectively, and for SAA they were 4 (4, 5) and 6 (5‐8) days, respectively, compared to a median (IQR) duration of AMD prescribing of 16 (12‐23) days (all P < .0001).Conclusions and Clinical ImportanceBiomarker concentrations normalized within 7 to 14 days. Serial measurements of CRP and SAA might aid identification of disease resolution and could help guide AMD prescription decision‐making.

Effects of lead exposure on biomarkers of thyroid and renal function tests among panel beaters in Enugu Metropolis, Nigeria.

Occupational lead (Pb) exposure causes multisystem effects at high and sustained low doses. However, there are inconsistencies in the dose-response effects on the thyroid and kidneys. This study aimed to assess the effects of Pb exposure on the biomarkers of thyroid and renal functions among panel beaters in Enugu Metropolis, Nigeria. This was a cross-sectional analytical study of 428-panel beaters selected using a multistage sampling technique. Blood lead (BPb), thyroid, and kidney biomarkers were analyzed using atomic absorption spectrometer at 238.3 nm wavelength, enzyme-linked immunosorbent assay, and automated chemistry analyzer, respectively. Analyses were performed using median, mean, Chi-square, correlation, and statistical significance. The median BPb levels were 10.0 μg/dl among participants with about half, 211 (49.3%) having BPb within reference levels. Though the mean values of thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), and creatinine (Cr) were within the reference values, the majority of 275 (64.25%) of the participants had non-euthyroid statuses. Significant differences were found in TSH (P = 0.001), thyroid status (P = 0.0129), and estimated glomerular filtration rate (P = 0.00384) between those with BPb within reference level and those with elevated levels. Though the mean levels of thyroid hormones and Cr were within their respective reference intervals, there was a preponderance of non-euthyroid status among participants in the present study with the majority of the participants falling within CKD grades 2 and 3.

A high sensitivity LC-MS/MS method for measurement of 3-methoxytyramine in plasma and associations between 3-methoxytyramine, metanephrines, and dopamine

IntroductionDiagnosis of pheochromocytoma and paraganglioma (PPGL) is aided by the measurement of metanephrine (MN) and normetanephrine (NMN). Research suggests that 3-methoxytyramine (3MT), a dopamine (DA) metabolite, may serve as a biomarker of metastasis in patients with paraganglioma. Considering the very low endogenous plasma 3MT concentrations (<0.1 nM), highly sensitive and specific methods for 3MT are needed. MethodsWe developed a simple method for measurement of 3MT. Sample preparation was performed using solid phase micro-extraction with the eluates injected directly onto the LC-MS/MS. Data acquisition was performed in multiple reaction monitoring mode with an instrumental analysis time of 3 min per sample. We evaluated the method’s performance and analyzed samples from healthy individuals and pathological specimens. ResultsThe limit of quantitation and upper limit of linearity were 0.03 nM and 20 nM, respectively. The intra-/inter-day imprecision for pooled plasma samples at concentrations of 0.04 nM, 0.2 nM, and 2 nM was 10.7%/18.3%, 4.5%/8.9%, and 3.1%/0.9%, respectively. Among samples with MN, NMN, or both MN and NMN above the reference intervals (RIs), 0%, 16% and 46%, respectively, showed 3MT greater than the proposed upper RI value of 0.1 nM; 12% of samples with DA above the RI had 3MT above 0.1 nM. ConclusionsThe developed method allowed accurate quantitation of 3MT in patient samples and would provide valuable information to clinicians diagnosing or monitoring patients with PPGL. High 3MT concentrations in patient samples with MN and NMN within the respective RIs may alert clinicians of the possibility of a DA-producing tumor.

Quantitative Analysis of Von Willebrand Factor (VWF) Multimers in Von Willebrand Disease (VWD) Patients Recruited through the Zimmerman Program for the Molecular and Clinical Biology of VWD

Quantitative Analysis of Von Willebrand Factor (VWF) Multimers in Von Willebrand Disease (VWD) Patients Recruited through the Zimmerman Program for the Molecular and Clinical Biology of VWD

Diatrizoate contrast agent study for luminal patency and visualization of the gastrointestinal tract in healthy rabbits (Oryctolagus cuniculus) and its influence on selected blood parameters and fecal quality

BackgroundThe aim of this study was to determine an effective dose of the contrast agent diatrizoate in healthy rabbits. MethodsThis study included 14 rabbits receiving three different dosages of a solution containing 300 mg iodine/mL and 600 mg diatrizoate/mL (Dose 1, 2 mL/kg; Dose 2, 7 mL/kg; Dose 3, 10 mL/kg). Full body radiographs were obtained at 0, 15, 30, 45 and 60 minutes, and 12 and 24 hours after oral administration. Blood samples 60 minutes and 24 hours after administration and fecal dry matter after 24 hours were compared to preliminary samples. ResultsRecommended doses and times for radiography for luminal patency and visualization of each gastrointestinal segment are given. The evaluated blood parameters were within their respective reference intervals throughout this study. However, significant changes (P < 0.05) could be observed. A decrease in hematocrit at all three doses administered, an increase in urea that persisted for more than 24 hours after administration of 2 mL/kg and 10 mL/kg, and a short-term increase in creatinine after administration of 7 mL/kg could be observed. Glucose and sodium were still increased after administration of 10 mL/kg after 24 hours, while potassium decreased after administration of all three doses. The chloride concentration was still increased after 24 hours after administration of 7 mL/kg. Administration of 7 mL/kg and 10 mL/kg resulted in a significant decrease in the dry matter of feces. Five rabbits developed self-limiting diarrhea after administration of 10 mL/kg. Conclusion and clinical relevanceDiatrizoate is a useful contrast agent in order to assess the passage through the intestine and achieve a good visualization of the gastrointestinal system.

Serum calcium determination with atomic absorption spectrophotometry and colorimetric method: association and predictive equations between them in cattle and sheep samples

The objectives of the present study were to compare the serum calcium (Ca) concentrations in cattle and sheep measured by the flame atomic absorption spectrophotometry (AAS) and those obtained with a colorimetric method (CM) and to generate equations that allow their prediction. Serum Ca concentration was determined in 50 dairy cattle and 50 dairy sheep non-hemolyzed blood samples with AAS and CM. The data were analyzed with paired sample t test and Bland–Altman plots were generated. Using a random number generator, 25 samples from each species were selected to create predictive equations between the two methods using Passing-Bablok regression analysis. The predictive equations were validated at the remaining 25 samples for each species using Bland–Altman plots. The average bias between the two methods was 5.5% for cattle and 18.1% for sheep samples. Mean Ca values determined with CM were significantly lower than those measured with AAS (P < 0.05) in both species. The use of the generated equations y = 0.706 + 0.727x for cattle and y = 0.744 + 0.833x for sheep (mmol/l) allows the prediction of AAS determined Ca (y) using CM determined Ca values (x) with average bias 1.8% for cattle and 1.9% for sheep. The two methods for calcium determination evaluated cannot be used interchangeably and the respective reference intervals and cut-off values should be taken into account to make clinical decisions in cattle and sheep. The use of the proposed equation for cattle is considered as acceptable for the calculation of bias corrected reference ranges and cut-off values.

Use of data mining in the establishment of age-adjusted reference intervals for parathyroid hormone

Background-AimAppropriately defined reference values are of vital importance for the correct interpretation of laboratory results. However, the implementation of in-house reference intervals by traditional methods is rare due to difficulties in the selection of reference individuals, so indirect methods are often alternatively used.Parathyroid hormone (PTH) is a crucial hormone for the metabolism of calcium and phosphorus whose result can lead to erroneous diagnoses and medical actions if adequate reference intervals are not readily available.Our goal was to obtain reference values ​​for adult population for PTH by using data mining. Based on possible new reference intervals, we also aimed to perform a retrospective evaluation of the individuals mistakenly classified. MethodsRetrospective observational study between 2014 and 2019. All requests from individuals aged ≥ 18 years were considered if PTH was requested together with serum creatinine, 25-hydroxyvitamin D, calcium, albumin and phosphate (within their respective reference intervals). PTH was measured on the Cobas e411 platform (Roche).Requests were grouped by age and sex. Differences among partitions were assessed by the Harris-Boyd’s test and reference intervals were determined by the non-parametrical calculation of percentiles 2.5 and 97.5. ResultsA total of 2279 laboratory requests were included. Reference intervals for PTH were seen to be sex-independent, but age-dependent reference intervals were needed: 18–39, 40–59 and >60 years.Based on the reference intervals obtained, up to 20.1% of individuals were misclassified. ConclusionsAppropriateness of PTH reference intervals would lead to a reduction in the number of additional tests and avoid wrong medical actions, thus improving not only patient safety, but also the healthcare system as a whole.

Effect of Season on Hematologic, Biochemical, and Hormonal Analytes in Rams of Two Breeds

Abstract Clinicopathological investigations are essential for the evaluation of the health status of ruminants. Apart from species-specific reference intervals, the effect of common biological factors should be considered for an accurate interpretation of laboratory data. The aim of this study was to evaluate the effect of season on hematologic and biochemical analytes, and serum total thyroxine and cortisol in adult rams of two breeds. Four blood samples (one every season) were collected from each ram. Complete blood count was performed on the Advia 120 (Siemens Healthcare Diagnostics, USA), while the differential leukocyte count was manually conducted. Biochemical and hormonal analyses were performed on Flexor E (Vital Scientific, The Netherlands), AVL 9180 (Roche Diagnostics, Belgium), and Immulite 1000 (Siemens Healthcare Diagnostics, USA), respectively. Linear mixed effects models (R language) were employed for statistical analyses. Forty-three (26 Chios, 17 Florina), adult, clinically healthy rams were included. Statistically significant (p&lt;0.05), mostly breed-independent seasonal differences were observed in almost all of the analytes. However, when assessing these differences in view of the respective reference intervals, only a few of them were considered biologically important. Specifically, mild hyperglycemia and mild decrease in the concentration of total calcium and inorganic phosphorus were detected in winter, while a mild increase in thyroxine concentration (autumn) and creatine kinase activity (spring and summer) was also noted. In conclusion, seasonal effects should be considered when evaluating laboratory results in rams; however, season does not appear to have an essential effect on the clinicopathological profile of rams reared in the Mediterranean region.

MON-442 Evaluation of Copeptin as a Surrogate for AVP in the Diagnosis of Water Metabolism Disorders

Arginine vasopressin (AVP) plays a key role in maintaining fluid balance and vascular tone and is useful in diagnosing diabetes insipidus (DI) and polyuria-polydipsia. Central DI is characterized by decreased AVP secretion leading to polyuria and polydipsia caused by diminished renal ability to concentrate urine. Alternatively, nephrogenic DI is characterized by a decrease in the ability to concentrate urine because of resistance of the distal nephron to AVP action. While AVP measurement can be diagnostic, reliable measurement of AVP can be hindered by several factors. AVP is tightly bound to platelets and is influenced by their number and incomplete removal, as well as pre-analytical processing. In addition, AVP is also highly unstable in isolated plasma - even at frozen temperatures. Copeptin comprises the C-terminal portion of the AVP precursor “pre-pro-vasopressin”. Equimolar amounts of AVP and copeptin released from this precursor during prohormone processing. Unlike the AVP molecule, copeptin is stable at room and refrigerated temperatures. In the current study, our objective was to confirm that copeptin can serve as a sensitive surrogate marker for AVP release in diagnosis. Our laboratory validated the B·R·A·H·M·S™ Copeptin proAVP assay on the automated KRYPTOR® platform. The measuring principle of the assay is based on Time-Resolved Amplified Cryptate Emission (TRACE®) technology, which measures the signal that is emitted with time delay from an immunocomplex. The molecules of copeptin present in the patient samples are sandwiched between the antibodies of the immunoassay. The intensity of the signal is proportional to the amount of copeptin. Extensive comparison studies, between AVP and copeptin, were conducted during the assay validation process. Approximately 245 patient samples previously tested for AVP were also tested in the copeptin assay. Using the respective reference intervals (RI) for AVP and copeptin, there was a 78.3% clinical concordance between the 2 assays; 53 samples (21.6%) were clinically discordant. Of the 245 patients, 4.5% (11 ) were above the AVP RI and 22.9% (56) were above the copeptin RI. Correlation plots showed a large degree of scatter between AVP and copeptin, which likely reflects the dissimilar stabilities of the two analytes. In conclusion, validation data suggest that there is clinical concordance for most patients tested using copeptin and AVP assays.

Mining the Age-Dependent Reference Intervals of B Vitamins from Routine Laboratory Test Results.

To describe the reference intervals of folate, vitamin B12, vitamin B6, and vitamin B1 by sex and age. The study was performed by gathering data on 55,811 subjects from 57 medical centers. Groups were categorized based on age and grouped according to statistical significance values. The reference values for the different groups were determined using the Bhattacharya and Hoffmann methods. Vitamin B1 and B6 values and folate (vitamin B9) levels between the sexes were statistically significantly increased in the group aged 0 to 10 years. Likewise, we witnessed a similar increase in vitamin B12 levels in the group aged 0 to 5 years. However, low vitamin B6 levels (P <.001) were detected in nongeriatric patients (aged 0-60 years), and the reference intervals (3.4-41.9 µg/L) also were significantly different from those in the geriatric group (aged 61-100 years; 2.0-29.4 µg/L). A lower vitamin B6 reference limit allows detection of subclinical vitamin deficiency more precisely in the geriatric group; respective reference intervals should be revised accordingly.

Effects of hemolysis and lipemia interference on kaolin-activated thromboelastography, and comparison with conventional coagulation tests

The effects of hemolysis and lipemia on thromboelastography (TEG) analysis have been scarcely evaluated in human samples, and neglected in clinical practice. We aimed to investigate the effects of in vitro mechanical hemolysis and lipemia on TEG analysis and conventional coagulation tests. Twenty-four healthy volunteers were enrolled in the study. Besides the controls, three groups with slight, moderate and severe mechanical hemolysis were constituted according to free hemoglobin (Hb) concentrations of 0.5–1.0, 2.0–6.0 and 7.0–13.0 g/L, respectively; and three groups with mild, moderate and high lipemia were established according to triglyceride concentrations of ∼6.0, ∼12.0, and ∼18.0 mmol/L, respectively. Four TEG parameters, reaction time (R), coagulation time (K), angle (α), and maximum amplitude (MA), were measured alongside conventional plasma tests including prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen (FIB) by mechanical method, and platelet count by optical method. Results showed that the median R and MA values at moderate and severe hemolysis and K at severe hemolysis exceeded respective reference intervals, and were considered unacceptable. Median values of TEG parameters in lipemic samples were all within reference intervals. Bias values of conventional plasma tests PT, APTT and FIB in hemolyzed or lipemic samples were all lower than the Clinical Laboratory Improvement Amendments (CLIA) allowable limits. Bias values of platelet count at moderate to severe hemolysis and lipemia exceeded the CLIA allowable limits. In conclusion, the detection of TEG was in general more affected by mechanical hemolysis than plasma coagulation tests. Pre-analytical variables should be taken into account when unexpected TEG results are obtained.

Spuriously high thyroid hormone concentrations measured by chemiluminescent immunoassay attributable to anti-iodothyronine antibodies in a dog

A 2.5-year-old female English setter was presented with clinicopathological findings suggestive of hypothyroidism. Thyroid-stimulating hormone (TSH: 4.3 ng/ml, normal <0.5), but also free thyroxine (FT4: 77 pmol/l, normal 7.7–48), total...

A Panel of Oxidative Stress Markers in Parkinson's Disease.

Oxidative stress may be the cause or effect of several pathogenetic processes such as neurodegenerative diseases. The aim of this paper was to evaluate the diagnostic efficacy in Parkinson's disease (PKD) of a panel of oxidative stress markers selected from the many proposed by the most recent literature. 23 molecules including both plasma and urinary oxidative markers such total radical oxygen species, homocysteine, biological antioxidant potential, glutathione, superoxide dismutase, uric acid, total bilirubin, iron, ferritin, coenzyme Q10, 3-nitrotyrosine, total lipoperoxides, 4-hydroxy-nonenal, and 8-hydroxy-deoxy-guanosine were determined both in PKD and aged control subjects. For each analyte and group, the respective reference intervals were determined. Statistical analysis was used to assess the existence of significant differences between intervals in order to indicate which markers can better characterize PKD and distinguish it from the control population. Some parameters were different in both groups when compared to those observed in younger subjects, supporting the hypothesis that aging is associated with an increase of oxidative stress. A peculiar increase of oxidative damage on nucleic acids was found in PKD, as well as a less efficient turnover of the DNA and an increase of protein peroxidation. Our results demonstrate that in PKD there is an increase of oxidative attack on nucleic acids and that the protein nitration is a characteristic phenomenon. These observations are in good agreement with the hypothesis that in PKD oxidative damage occurs that counter-regulatory systems attempt to balance, but inefficiently.

Effects of racing on reticulocyte concentrations in Greyhounds

Greyhounds have several hematologic variables that are outside of the respective reference intervals of other dog breeds. In addition, increases in HCT, total protein and HGB concentration, and RBC and WBC counts occur immediately after exercise; these values return to resting values within a few hour after racing. This study evaluated the effects of exercise on the concentration of reticulocytes in circulating blood in racing Greyhounds. We hypothesized that reticulocyte numbers are significantly increased immediately after a race, and return to baseline within one to 2 h postrace. Fifty actively racing Greyhounds at the Wheeling Island Racetrack and Casino were included in the study. Samples were collected by jugular venipuncture one day prior to racing at the kennel (resting), immediately after racing, and one to 2 h after the race (recovery). Reticulocyte counts were determined with an IDEXX ProCyte Dx Hematology Analyzer (IDEXX Laboratories, Inc., Westbrook, ME, USA). Due to a nonparametric distribution, the results were statistically compared using the Friedman test. Reticulocyte concentrations were significantly different among the 3 sample collection times (P < .0001). There was a significant increase in reticulocyte concentration immediately after racing (P < .001); one to 2 h after racing, the reticulocyte numbers decreased significantly (P < .001) to counts comparable to resting samples. The increase in reticulocyte concentration is probably related to splenic contraction secondary to the release of catecholamines, although premature bone marrow release could also account for these changes. Thus, it is important to consider a Greyhound's activity and degree of excitement when interpreting selected hematologic data in a clinical setting.

Increased Serum Creatine Kinase

A 38-year-old white male taxi driver was referred to a lipid clinic by his general practitioner for management of combined hyperlipidemia. He was a smoker with a 20 pack-year history. His father had died of myocardial infarction at age 55 years. Examination of this patient revealed a blood pressure of 136/99 mmHg and a body mass index of 29 kg/m2, with no clinical signs of hyperlipidemia. Cholesterol testing revealed a total serum cholesterol value of 251 mg/dL (6.5 mmol/L; reference interval, 3.7–7.0 mmol/L), an HDL concentration of 30.9 mg/dL (0.8 mmol/L; reference interval, 0.7–1.8 mmol/L), and triglycerides of 539 mg/dL (6.1 mmol/L; reference interval, 20%, indicative for primary prevention of hyperlipidemia with a statin, after changes in lifestyle (1). Baseline biochemical investigations before starting the statin showed a serum creatine kinase (CK)4 activity of 889 U/L (reference interval, 24–195 U/L) and an alanine aminotransferase activity of 61 U/L (reference interval, <50 U/L). The results of other tests were within their respective reference intervals: total bilirubin, 0.8 mg/dL (13 μmol/L; reference interval, <14 μmol/L); alkaline phosphatase, 95 U/L (reference interval, <150 U/L); and γ-glutamyltransferase, 49 U/L (reference interval, <50 U/L). The results of other laboratory investigations (including renal function, blood count, serum vitamin B12, folate, serum protein electrophoresis, antinuclear antibodies, C-reactive protein, and thyroid function) were normal. At 30 years of age, the patient's mother had been diagnosed with lower limb muscle weakness, which made her unable to dorsiflex her feet. His 48-year-old brother and 38-year-old maternal half-brother were both fine. ### QUESTIONS TO CONSIDER 1. What conditions can cause increased serum CK? 2. What other testing would be useful to help determine the cause of the increased CK? 3. Given this patient's family history, what condition should be …

Novel lipoprotein density profiling in healthy dogs of various breeds, healthy miniature schnauzers, and miniature schnauzers with hyperlipidemia

BackgroundDespite the importance of abnormalities in lipoprotein metabolism in clinical canine medicine, the fact that most previously used methods for lipoprotein profiling are rather laborious and time-consuming has been a major obstacle to the wide clinical application and use of lipoprotein profiling in this species. The aim of the present study was to assess the feasibility of a continuous lipoprotein density profile (CLPDP) generated within a bismuth sodium ethylenediaminetetraacetic acid (NaBiEDTA) density gradient to characterize and compare the lipoprotein profiles of healthy dogs of various breeds, healthy Miniature Schnauzers, and Miniature Schnauzers with primary hypertriacylglycerolemia. A total of 35 healthy dogs of various breeds with serum triacylglycerol (TAG) and cholesterol concentrations within their respective reference intervals were selected for use as a reference population. Thirty-one Miniature Schnauzers with serum TAG and cholesterol concentrations within their respective reference intervals and 31 Miniature Schnauzers with hypertriacylglyceridemia were also included in the study.ResultsThe results suggest that CLPDP using NaBiEDTA provides unique diagnostic information in addition to measurements of serum TAG and cholesterol concentrations and that it is a useful screening method for dogs with suspected lipoprotein metabolism disorders. Using the detailed and continuous density distribution information provided by the CLPDP, important differences in lipoprotein profiles can be detected even among dogs that have serum TAG and cholesterol concentrations within the reference interval. Miniature Schnauzers with serum TAG and cholesterol concentrations within the reference interval had significantly different lipoprotein profiles than dogs of various other breeds. In addition, it was further established that specific lipoprotein fractions are associated with hypertriacylglyceridemia in Miniature Schnauzers.ConclusionsThe results of the present study suggest that density gradient ultracentrifugation using NaBiEDTA is a useful screening method for the study of lipoprotein profiles in dogs. Therefore, this method could potentially be used for diagnostic purposes for the separation of dogs suspected of having lipoprotein abnormalities from healthy dogs.