Specific Reference Intervals Research Articles

Hematological indices reference intervals for a healthy Arab population in Qatar: Effect of age, gender, and geographic location.

Hematologic reference intervals vary with gender, age, ethnicity, and geographic area. Therefore, local or national laboratory reference ranges are essential to enhance the accuracy when diagnosing health conditions. Still, no comprehensive list of reference ranges tailored to the Arab population living in Qatar. Accordingly, this study aims at establishing a hematology reference guide for Arabs in Qatar.This is a retrospective study where 750 healthy volunteers (18–69 years) from 2015 to 2019 were included, analyzed by an automated hematology analyzer. Arab adults were divided into African (Egypt, Libya, Tunisia, Morocco) and Asian (Syria, Lebanon, Jordon, Palestine, Qatar). The Cell-Dyn and Sysmex were used for measuring hematological parameters.The mean +/- 2SD were established for all the study groups. Arab males had significantly higher Hb, Hct, red cell distribution width, absolute neutrophil count, lymphocytes, and monocyte counts than females. Asian-Arab males had significantly higher Hb concentration and higher WBC, lymphocytes, and eosinophils than African Arabs. Asian-Arab young (>18: < 40 years) males had significantly higher Hb and lymphocytes and lower monocytes than older males (>40 years). African-Arab young males had significantly higher lymphocytes and lower monocytes than older males. Asian-Arab young females had higher WBC and absolute neutrophil count than older Asian Arabs.The findings of this study will help in establishing specific reference intervals in the Arab world. The differences in hematology reference intervals considering age, gender, and geographical location highlight the importance of establishing blood reference intervals in each country considering the ethnic diversity of each country.

Validation of lipid profile measurement methods and establishment of reference values in a sub-Saharan African population.

Validated reference values and procedures are needed to ensure optimal diagnosis of dyslipidemia in sub-Saharan Africa. We aimed to validate an analysis method and establish reference intervals of lipid profile parameters in Cameroonians using this method. On a cross-sectional study conducted from November 2019 to August 2020 in Yaoundé, we have analyzed blood samples with Cobas® 6000. We subscribed to ASQUALAB's External Quality Assessments (EQA) and Outsourced Internal Quality Controls (IQC). Reproducibility, repeatability, correctness accuracy and uncertainty were evaluated using IQC. Consenting adult participants were conveniently sampled, excluding those with any condition that may affect lipid profile. Descriptive statistics were reported accordingly, agreement was assessed with Bland-Altman analysis, and reference intervals were defined according to CLSI and IFCC recommendations. The coefficients of variation for repeatability, reproducibility, and correctness bias ranged between 0.6% and 6%, with all values within the normal range. Expanded uncertainty of total cholesterol, HDL and triglycerides measurements were, respectively, 0.45, 0.24 and 0.18. We included 422 participants with a mean age of 30.2 (10.9) years and 248 (58.8%) females. Reference intervals for total cholesterol, HDL, triglycerides and LDL were, respectively, 2.94-6.02 mmol/L, 0.90-2.06 mmol/L, 0.35-1.36 mmol/L, 1.37-4.13 mmol/L. These intervals were similar between sex and ethnic groups, but lower in younger participants. Lipid profile measurement with Cobas® 6000 is a reliable and accurate analysis in our context. Specific reference intervals must be used in African population, with further studies need for different age subgroups.

Age and sex specific reference intervals of 13 hematological analytes in Chinese children and adolescents aged from 28days up to 20years: the PRINCE study.

Pediatric Reference Intervals in China (PRINCE) is a nationwide initiative that aims to establish and validate harmonized reference intervals (RIs) for Chinese children and adolescents, in which 15,150 healthy volunteers aged up to 20years were recruited from 11 centers to establish RIs and 7,557 children and adolescents were enrolled from 21 centers to validate RIs. The complete blood cell counts (CBC) of venous whole blood were measured by hematology analyzers through Sysmex systems in different centers. Age- and sex-specific RIs were calculated according to the guidelines. Unlike adults with certain levels of analyte concentrations, hematological parameters of children changed through growth and development. Red blood cell counts, hemoglobin, and hematocrit increased with age, and revealed higher concentrations in boys than girls after puberty. White blood cell counts and platelet counts showed significant higher levels than adults before 2years of age, and then gradually decreased without distinct sex differences. In addition, lymphocyte counts decreased with age while neutrophil counts showed an opposite trend. The lower and upper limits of pediatric RIs of CBC were different from those of adults. The validation of RIs indicated that the PRINCE study provided a version of RIs suitable for most of regions in China. This first harmonized pediatric RIs of CBC across China provided a robust database to understand the dynamic changes of hematologic parameters from birth to adolescence, and will contribute to clinical diagnosis and prognosis evaluation for pediatric patients as well.

Comparison of Symptoms and Antibody Response Following Administration of Moderna or Pfizer SARS-CoV-2 Vaccines.

Moderna (mRNA-1272) and Pfizer (BNT162b2) SARS-CoV-2 vaccines demonstrate favorable safety and efficacy profiles, but direct comparison data are lacking. To determine the vaccines' side effect profiles and expected antibody responses. These data may help personalize vaccine selection and identify individuals with a suboptimal vaccine response. One hundred forty-nine healthy, largely seronegative adults were assigned Moderna (n = 79) or Pfizer (n = 70). Following the second dose, participants completed a survey documenting their side effects. Serum was collected 0 to 4 days prior to dose 2, and 14 ± 4 days, 30 ± 4 days, 90 ± 10 days, and 180 ± 20 days after dose 2. Convalescent serum specimens were collected 32 to 54 days from donors after a polymerase chain reaction-confirmed SARS-CoV-2 infection (n = 20). Anti-spike antibodies were measured using the Roche Diagnostics Elecys Anti-SARS-CoV-2 S assay on a Roche cobas e801 instrument. Participants receiving the Moderna vaccine experienced side effects with greater frequency and severity. Both vaccines elicited a robust antibody response, but median signal was higher in Moderna recipients. Symptom severity decreased with age. Antibody response in Pfizer recipients negatively correlated with age. Antibody response decreased after 6 months (84% reduction in Moderna, 79% Pfizer), but values remained greater than for convalescent donors. Antibody response did not correlate with gender or symptom severity. Moderna may be preferred in individuals in need of greater immune stimulation (eg, older individuals), whereas Pfizer may be preferred in those concerned about vaccine reactions. Anti-spike antibody signal varies by vaccine, so specific reference intervals will be needed to identify individuals with a suboptimal response.

Reference interval of antithrombin, protein C, and protein S activities in healthy adults in Iran, the effect of age, sex, oral contraceptive intake, and menopause.

Antithrombin (AT), protein C (PC), and protein S (PS) are natural anticoagulant proteins that deficiency in each of them is associated with an increased risk of venous thromboembolism.The overlapping of plasma levels of AT, PC, and PS between healthy individuals and heterozygote carriers poses significant challenges in precise diagnosis. This study aimed to evaluate the effect of most influencing variables on plasma levels of these proteins and propose specific reference intervals to improve the interpretation of the laboratory results. This study was conducted on 1464 individuals who were referred to Massoud medical laboratory, Tehran, Iran, from 2019 to 2020. AT and PC were measured through chromogenic assay and PS plasma level with the clot-based assay. A multivariable linear regression model was performed to evaluate the effect of sex, age, oral contraceptive (OCP) intake, and menopause state. Normal deviate z value was used for different subgroups to justify the need for a separate reference interval. 1200 verified healthy individuals (434males and 766 females), aged between 18 and 69years were included in the study. The mean±SD age of the participants was 39.78±11.79years. The age-related effects for AT were found in men. In females, increasing age was associated with a rise in AT, PC, and PS plasma levels. No sex difference was found in AT plasma level. OCP-taking is associated with a decrease in AT and an increase in PC plasma levels. This is the largest study ever conducted on healthy individuals in the Iranian population, using specific reference interval results in accurate diagnosis of true AT, PC, and PS deficiency.

Mild Anemia May Affect Thyroid Function in Pregnant Chinese Women During the First Trimester.

BackgroundPregnant women are often susceptible to anemia, which can damage the thyroid gland. However, compared with moderate and severe anemia, less attention has been paid to mild anemia. The purpose of this study was to evaluate the effect of mild anemia on the thyroid function in pregnant women during the first trimester.MethodsA total of 1,761 women in the first trimester of their pregnancy were enrolled from Shenyang, China, and divided into mild anemia and normal control groups based on their hemoglobin levels. Thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) levels were compared between the two groups.ResultsThe TSH levels of pregnant women with mild anemia were higher than those of pregnant women without mild anemia (p < 0.05). Normal control women were selected to set new reference intervals for TSH, FT3, and FT4 levels during the first trimester, which were 0.11–4.13 mIU/l, 3.45–5.47 pmol/l, and 7.96–16.54 pmol/l, respectively. The upper limit of TSH 4.13 mU/l is close to the upper limit 4.0 mU/l recommended in the 2017 American Thyroid Association (ATA) guidelines, indicating that exclusion of mild anemia may reduce the difference in reference values from different regions. Mild anemia was related to 4.40 times odds of abnormally TSH levels (95% CI: 2.84, 6.76) and 5.87 increased odds of abnormal FT3 (95% CI: 3.89, 8.85). The proportion of hypothyroidism and subclinical hypothyroidism in patients with mild anemia was higher than that in those without anemia (0.6% vs. 0, p = 0.009; 12.1% vs. 1.9%, p < 0.001). Mild anemia was related to 7.61 times increased odds of subclinical hypothyroidism (95% CI: 4.53, 12.90).ConclusionsMild anemia may affect thyroid function during the first trimester, which highlights the importance of excluding mild anemia confounding when establishing a locally derived specific reference interval for early pregnancy.

Influence of Turkish origin on hematology reference intervals in the German population

Reference intervals for laboratory test results have to be appropriate for the population in which they are used to be clinically useful. While sex and age are established partitioning criteria, patients’ origin also influences laboratory test results, but is not commonly considered when creating or applying reference intervals. In the German population, stratification for ethnicity is rarely performed, and no ethnicity-specific hematology reference intervals have been reported yet. In this retrospective study, we investigated whether specific reference intervals are warranted for the numerically largest group of non-German descent, individuals originating from Turkey. To this end, we analyzed 1,314,754 test results from 167,294 patients from six German centers. Using a name-based algorithm, 1.9% of patients were identified as originating from Turkey, in line with census data and the algorithm’s sensitivity. Reference intervals and their confidence intervals were calculated using an indirect data mining approach, and Turkish and non-Turkish reference limits overlapped completely or partially in nearly all analytes, regardless of age and sex, and only 5/144 (3.5%) subgroups’ reference limits showed no overlap. We therefore conclude that the current practice of using common reference intervals is appropriate and allows correct clinical decision-making in patients originating from Turkey.

Protein Electrophoresis of Serum and Heparinized Plasma in the Common Mynah (Acridotheres tristis).

Although serum protein electrophoresis is a diagnostic tool available through many veterinary laboratories, there currently are no reference intervals for protein fractions in healthy common mynahs (Acridotheres tristis). Therefore, electrophoretic patterns of proteins in serum and heparinized plasma of the common mynah were evaluated. Blood specimens were collected from 55 healthy adult common mynahs of unknown age (26 males and 29 females). The serum total protein and protein fractions were measured using the biuret method followed by cellulose acetate electrophoresis (CAE). The serum level of albumin was compared with bromocresol green (BCG) dye-binding and CAE methods. Four protein fractions, including albumin and α, β, and γ globulins, were recorded in the electrophoretogram of serum specimens. Sex appeared to have no significant effect on the measured parameters. The serum BCG albumin fraction was significantly higher than the CAE albumin fraction (P = .01). Also, the comparison of total protein and protein fractions in serum and plasma specimens of 25 of the 55 birds sampled showed that total protein (Cohen index d = 0.66, P = .03), gamma globulin (d = 1.13, P = .00), and total globulin (d = 0.67, P = .00) in plasma samples were significantly higher than those in serum samples. The results of this study provide the specific reference intervals for total protein and protein fractions in common mynahs, which are essential for proper interpretation of laboratory results and also revealed that the albumin measurement by the BCG method yields unreliable results in common mynahs.

ASSESSMENT OF URINARY IODINE LEVEL AND ITS RELATION TO THYROID FUNCTION IN SAMPLE OF EGYPTIAN PREGNANT FEMALES IN 1ST TRIMESTER

Background: Thyroid disorders are considered the second most common endocrine disorders affecting women during their reproductive years and can impact up to 4% of all pregnancies. Of all thyroid disorders, hypothyroidism is the most prevalent, impacting approximately 2- 3% of all pregnancies. Hyperthyroidism is far less prevalent, impacting approximately 0.2% of all pregnancies.Aim of the Work: To assess the level of urinary iodine in 1st trimester of pregnancy and its relation with thyroid hormones level and autoimmunity status.Subjects and Methods: To elucidate this aim 100 healthy pregnant female in their 1st trimester of pregnancy were included in the study. They were collected from Obstetrics and Gynecology Department El Demerdash hospital and Dar El shefa Hospital in the period from September, 2020 to November, 2020.Results: Median urinary iodine was 55(41.0-76.0) μg/l and their was99 females had insufficient iodine intake less than 150μg /l, one had adequate intake (150-249) μg /l and none showed more than necessary intake (250-499) μg /l or excessive intake more than 500 μg /l. As regard thyroid ultrasound there was normal Thyroid volume in 94 subjects,(94.0%)., increased volume in 6 subjects (6%). There was a Significant negative correlation between each of the following the age and the gestational age; and urinary iodineConclusion: There was a significant iodine deficiency in pregnant women within the study area, indicating that some women may need to increase their iodine intake during pregnancy. Additionally, diagnosis and treatment of thyroid dysfunction during pregnancy should be based on pregnancy and method specific reference intervals, and more detailed staging is needed to assess pregnant women's thyroid function.

Distribution of HOMA-IR in a population-based cohort and proposal for reference intervals.

Insulin resistance (IR) is a hallmark of type 2 diabetes mellitus (DM). The homeostatic model assessment of insulin resistance (HOMA-IR) provides an estimate for IR from fasting glucose and insulin serum concentrations. The aim of this study was to obtain a reference interval for HOMA-IR for a specific insulin immunoassay. The Gutenberg Health Study (GHS) is a population-based, prospective, single-center cohort study in Germany with 15,030 participants aged 35-74years. Fasting glucose, insulin, and C-peptide were available in 10,340 participants. HOMA-IR was calculated in this group and three reference subgroups with increasingly more stringent inclusion criteria. Age- and sex-dependent distributions of HOMA-IR and reference intervals were obtained. In a substudy three insulin assays were compared and HOMA-IR estimated for each assay. Among the 10,340 participants analyzed there were 6,590 non-diabetic, 2,901 prediabetic, and 849 diabetic individuals. Median (interquartile range [IQR]) HOMA-IR was 1.54 (1.13/2.19), 2.00 (1.39/2.99), and 4.00 (2.52/6.51), respectively. The most stringently selected reference group consisted of 1,065 persons. Median (IQR) HOMA-IR was 1.09 (0.85/1.42) with no significant difference between men and women. The 97.5th percentile was 2.35. There was a non-significant trend towards higher values with older age. Comparison of three immunoassays for insulin showed an unsatisfactory correlation among the assays and systematic differences in calculated HOMA-IR. We present HOMA-IR reference intervals for adults derived by more or less stringent selection criteria for the reference cohort. In addition we show that assay specific reference intervals for HOMA-IR are required.

Age and sex-specific reference intervals for prooxidant-antioxidant balance, anti-heat-shock protein 27 (anti-hsp27), and routine laboratory tests in the middle-aged adult population.

We aimed to define specific reference intervals (RIs) for 11 biomarkers including inflammatory and oxidative stress biomarkers, liver, and renal function tests in a healthy Iranian adult population for the first time. CLSI Ep28-A3 guidelines were then used to calculate accurate age- and sex- as well as body mass index (BMI)-specific RIs. RIs for studied biomarkers showed no significant age and sex-specific differences, except for uric acid, which had higher concentrations in men when compared to women. Additionally, after partitioning the participants based on the BMI with a cutoff point of 25 kg/m2 , only the levels of hs-CRP were positively associated with higher BMI (RI for BMI>25: 0.51-7.85 mg/L and for BMI<25: 0.40-4.46 mg/L). RI for PAB and anti-hsp-27 were reported 4.69-155.36 HK and 0.01-0.70 OD in men and women aged 35-65 years old. Partitioning by sex and BMI was only required for uric acid and hs-CRP, respectively, while other biomarkers required no partitioning. These results can be expected to valuably contribute to improve laboratory test result interpretation in adults for improved monitoring of various diseases in the Iranian population.

Optimized procedures for testing plasma metanephrines in patients on hemodialysis

Diagnosis of pheochromocytomas and paragangliomas in patients receiving hemodialysis is troublesome. The aim of the study was to establish optimal conditions for blood sampling for mass spectrometric measurements of normetanephrine, metanephrine and 3-methoxytyramine in patients on hemodialysis and specific reference intervals for plasma metanephrines under the most optimal sampling conditions. Blood was sampled before and near the end of dialysis, including different sampling sites in 170 patients on hemodialysis. Plasma normetanephrine concentrations were lower (P < 0.0001) and metanephrine concentrations higher (P < 0.0001) in shunt than in venous blood, with no differences for 3-methoxytyramine. Normetanephrine, metanephrine and 3-methoxytyramine concentrations in shunt and venous blood were lower (P < 0.0001) near the end than before hemodialysis. Upper cut-offs for normetanephrine were 34% lower when the blood was drawn from the shunt and near the end of hemodialysis compared to blood drawn before hemodialysis. This study establishes optimal sampling conditions using blood from the dialysis shunt near the end of hemodialysis with optimal reference intervals for plasma metanephrines for the diagnosis of pheochromocytomas/paragangliomas among patients on hemodialysis.

Harmonization of LC-MS/MS Measurements of Plasma Free Normetanephrine, Metanephrine, and 3-Methoxytyramine.

Plasma-free normetanephrine and metanephrine (metanephrines) are the recommended biomarkers for testing of pheochromocytoma and paraganglioma (PPGL). This study evaluated the status of harmonization of liquid chromatography-tandem mass spectrometry-based measurements of plasma metanephrines and methoxytyramine and clinical interpretation of test results. 125 plasma samples from patients tested for PPGLs were analyzed in 12 laboratories. Analytical performance was also assessed from results of a proficiency-testing program. Agreement of test results from different laboratories was assessed by Passing-Bablok regression and Bland-Altman analysis. Agreement in clinical test interpretation based on laboratory specific reference intervals was also examined. Comparisons of analytical test results by regression analysis revealed strong correlations for normetanephrine and metanephrine (R ≥ 0.95) with mean slopes of 1.013 (range 0.975-1.078), and 1.019 (range 0.963-1.081), and intercepts of -0.584 (-53.736 to 54.790) and -3.194 (-17.152 to 5.933), respectively. The mean bias between methods was 1.2% (-11.6% to 16.0%) for metanephrine and 0.1% (-18.0% to 9.5%) for normetanephrine. Measurements of 3-methoxytyramine revealed suboptimal agreement between laboratories with biases ranging from -32.2% to 64.0%. Interrater agreement in test interpretation was >94% for metanephrine and >84% for normetanephrine; improvements in interrater agreement were observed with use of harmonized reference intervals, including age-specific cut-offs for normetanephrine. Analytical methods for metanephrines are well harmonized between laboratories. However, the 16% disagreement in test interpretation for normetanephrine suggests use of suboptimal method-dependent reference intervals for clinical decision-making for this metabolite. Improved analytical methods and reference interval harmonization are particularly required for 3-methoxytyramine.

Calculation of indirect reference intervals of plasma lipase activity of adults from existing laboratory data based on the Reference Limit Estimator integrated in the OPUS::L information system

Abstract Objectives Most laboratories have difficulties to determine their own reference intervals for the diagnostic evaluation of patient results by direct methods. Therefore, data is often just taken from the literature or package inserts of the analytical tests. Methods The section on Reference Limits of the German Society for Clinical Chemistry and Laboratory Medicine (DGKL) first uploaded the Reference Limit Estimator (RLE) as an R-program with MS Excel-interface on the DGKL home page and now this tool is implemented in the commercial Laboratory Information System OPUS::L (OSM AG Essen, Germany). We used this OPUS::L “Population specific Reference Limits” tool online with our laboratory database. First calculations were done using the example of lipase. Results The manufacturer’s original reference interval for lipase 12–53 U/L (adults) was changed to age dependent upper reference limits of &lt;41 U/L (&lt;20 years), &lt;60 U/L (20–80 years) and &lt;70 U/L (&gt;80 years). Conclusions By means of the OPUS::L “Population specific Reference Limits” tool we were able to establish our laborarotry specific reference interval for plasma lipase activity. The new reference limits helped to solve an old problem of implausible low elevated lipase values.

Pediatric Thromboelastograph 6s and Laboratory Coagulation Reference Values.

Specific reference intervals (RIs) facilitate accurate interpretation of results. Coagulation assay results may vary by demographics and also between reagents and analyzers used. Current Thromboelastograph 6s (TEG 6s) Hemostasis Analyzer RIs were generated from adult samples. To generate reagent analyzer-specific pediatric RIs for TEG 6s and coagulation parameters. A prospective, observational, single-center study of healthy children undergoing general anesthesia (January 3, 2017 to January 3, 2019). Venous blood samples were obtained for TEG 6s (Kaolin, Kaolin-Heparinase, Rapid and Functional Fibrinogen assays) and coagulation parameters (activated partial thromboplastin time, prothrombin time, thrombin clotting time, Echis time, antithrombin activity, and fibrinogen concentration using Instrumentation Laboratory ACL-TOP analyzers). Differences between activated partial thromboplastin time and prothrombin time reagents were investigated using mixed-effects regression, comparing maximum coefficients-of-variation with assay-specific allowable variation. RIs (lower/upper limits 2.5th of 97.5th percentiles) were generated using the following 2 methods: within discrete age-groups (neonates [<1 month], infants [1 month-1 year], young children [1-5 years], older children [6-10 years], and adolescents [11-16 years]), and modeled as functions of age and/or sex using quantile regression, including significant fractional polynomial and interaction terms. Variation between prothrombin time and activated partial thromboplastin time assays using different reagents was clinically significant. Reagent-analyzer specific pediatric RIs were generated using data from 254 children. Discrete and model-based RIs varied by age for all coagulation parameters and TEG 6s variables in all assays. We report reagent-analyzer specific pediatric RIs for TEG 6s and coagulation parameters. Observed variation reinforces recommendations for laboratory-specific RIs. These findings improve accuracy of interpretation of clinical results, provide a foundation for comparison and validation of tests in pathology, and illustrate feasibility and advantages of model-based RI approaches.

Vitamin D Toxicosis in a Blue-Tongued Skink (Tiliqua scincoides) Presented with Epistaxis and Tongue Discoloration

A 10-yr-old intact blue-tongued skink (Tiliqua scincoides) of unknown sex presented for epistaxis and dyspnea. On physical examination, dysecdysis, necrosis of the tip of the tail, and a pink discoloration of the proximal third of the tongue were noted in addition to epistaxis, dyspnea, and tachypnea. Clinical pathology findings included marked polychromatophilia, moderate heterophilia with signs of toxicity, a regenerative left shift, and moderate hyperglycemia. Because of the suspicion of an infectious etiology, antibiotics were prescribed. Meloxicam was also administered without clinical improvement. Swelling of the pharyngeal area was noted on whole-body computed tomographic and magnetic resonance imaging. Oro-pharyngeal endoscopic-guided biopsies were performed under general anesthesia. Histology was consistent with moderate erosion and goblet cell hyperplasia. Plasma 25-hydroxyvitamin D3 concentration was 768 nmol/L and was interpreted as possible vitamin D toxicosis. Prednisolone was prescribed to enhance calciuresis and treat potential vasculitis, but the skink was ultimately euthanized. Histopathologic examination was consistent with vitamin D toxicosis. The diet of this skink mostly consisted of greens dusted with a supplement containing calcium and vitamin D3. This case report describes the challenges associated with antemortem diagnosis of a vitamin D toxicosis, even with current imaging techniques. It highlights that specific reference intervals should be established for 25-hydroxyvitamin D3 and ionized calcium concentrations in various reptile species. Clinicians presented with a blue-tongued skink displaying a pink tongue or tail necrosis should consider vitamin D toxicosis in their differential diagnosis.

Thyroid function tests in euthyroid pregnant and non-pregnant women

Background: Pregnancy is associated with significant but reversible changes in thyroid functions, which may exacerbate thyroid disorders or improve thyroid disorders. Objectives: The present study was done to find out changes in thyroid function tests in each trimester in normal pregnant women when compared with non-pregnant women in a tertiary healthcare center. Materials and Methods: A cross-sectional study of 80 euthyroid women in the age group of 16–40 years was done. Twenty were non-pregnant and 20 were from first, second, and third trimesters each. Serum level measurement of T3, T4, and TSH was done with chemiluminescence technique. Results: The results of the study showed a progressive decrease in the mean values of FT3 and FT4, with a significant decrease in FT3 (P-value < 0.0001) and FT4 (P-value =0.0129) only in the third trimester. There was a progressive increase in the mean TSH levels through the pregnancy; however, there was no significant increase when compared with the non-pregnant women. Conclusion: There is a significant increase in serum T3 and T4 in pregnancy. Specific reference intervals should be used to identify the patients at risk and to take early interventions of treatment.

Definition of Reference Range for the Immature Granulocytes Parameter Provided by a Hematology Analyzer.

Some pathologies or physiological changes may show forms of granulocytes in peripheral blood. Hematology analyzers have brought new parameters such as the detection of immature granulocytes (IG), which may be useful biomarkers. The objective of this study was determined the IG count in a control group to establish the reference range. A group of healthy donors was used to obtain the reference value of IG in the laboratory of the Hospital de Clínicas de Porto Alegre. The reference range of IG (n = 115) was 0 - 0.06 x 109/L and 0 - 0.63%. This reference interval was similar to that of previous studies. The determination of the specific reference interval for each region is an important tool in the direct application of biomarkers in clinical laboratory routines. The use of reference values is essential so that the true positive cases for microscopic review are detected without a large number of false positives, which would impair laboratory efficiency.

Hematological Indices Reference Intervals for Healthy Arab Population in Qatar: Effect of Age, Gender, Geographic Location and ABO Blood Group

Introduction: The majority of physicians' medical judgments are based on clinical information supported by laboratory reports . The availability of a reference interval for different lab values facilitates the process of interpretation . Complete blood count (CBC), testing is one of the most frequently performed hematology test in any clinical setting. Analysis of CBC by hematology analyzers is an indispensable means in the evaluation of many acute and chronic disorders including traumatic, infectious, immunological, and hematological diseases. Establishment of a normal reference interval is essential for accurate clarification of the disease diagnosis as well as for follow up. CBC techniques have improved significantly, and the accurate automated methods have now substituted manual methods. In addition, various novel blood cell parameters have been developed alongside to aid in diagnosis and management of several blood disorders . However significant differences exist in the reference intervals based on age, gender, ethnicity, genetic differences, environmental factors, and geographical location.. Dietary habits and occupational exposures are factors that have been shown to affect reference interval . Therefore, there is a requirement for each country to establish its own reference intervals. Country-specific reference intervals for CBC of adult peripheral blood have been established in many countries around the world; however, there have been no specific comprehensive studies in Arab population in Qatar based on age, gender, geographic location and ABO blood groups. To the best of our knowledge, this is the first study in Qatar that investigated CBC reference intervals in relation to age, gender, and blood grouping which can now be used as a reference when evaluating patient samples in Qatar. Methods: Venous blood specimens were collected from 720 healthy randomly selected individuals aged 18 to 69 years from 2018 to 2019 and analyzed by Sysmex NX-10 and NX -20 automated hematology analyzers. Results were statistically analyzed and compared by gender, age, and ABO blood group. Arab adults were divided into African Arabs (Egypt, Libya, Tunisia, Morocco) and Asian Arabs (Syria, Lebanon, Jordon, Palestine, Qatar). The lower and upper reference limits of the hematology reference intervals were established at the -2 SD and +2SD respectively. Results: Reference intervals were calculated for all the hematology parameters which included red blood cell, white blood cell and differential count, and platelet parameters. Arab males had significantly higher Hb, Hct, RDW, ANC, lymphocytes and monocyte counts compared to adult females. Asian-Arab males had significantly higher Hb concentration and higher WBC, lymphocytes and eosinophil counts compared to African- Arab males. Asian Arab young males had significantly higher Hb level and lymphocyte count and lower monocytes counts compared old males. African Arab young males had significantly higher lymphocyte and lower monocytes counts compared to old males. Asian- Arab young females had higher WBC, ANC counts compared to old Asian Arab females. No statistical difference in the studied hematological parameters was detected among the three groups with different ABO subgroups Conclusions: Data from this study established specific reference intervals which could be considered for general use in the Arab world. The differences in hematology reference intervals in respect to age, sex and geographical location highlights the necessity to establish reference intervals for venous blood parameters among the healthy population in each country or at least in each region. Disclosures No relevant conflicts of interest to declare.

Trimester-Specific Reference Intervals of Serum Urea, Creatinine, and Uric Acid Among Healthy Pregnant Women in Zhengzhou, China.

To verify the differences in serum levels of urea, creatinine, and uric acid (UA) between pregnant and nonpregnant women and establish specific reference intervals of serum urea, creatinine, and UA for pregnant women, and thus help for the detection of kidney disease in pregnancy. Based on the selection criteria, 1312 apparently healthy pregnant women and 1301 nonpregnant women were enrolled in this study. The levels of serum urea, creatinine, and UA were compared between the pregnant and nonpregnant women. The differences in the 3 indicators among different age groups and trimesters in pregnant women were studied. Finally, reference intervals were established by nonparametric methods according to the recommendation of Clinical and Laboratory Standards Institute guideline C28-A3. Compared with nonpregnant women, pregnant women had a significantly lower level of serum urea, creatinine, and UA (all P <.01), and no significant age-related differences in the 3 indicators were observed among the pregnant women (P >.05). However, the levels of these indicators were significantly different among the 3 trimesters (all P <.01 or P =.01). Accordingly, trimester-specific reference intervals of serum urea (1.6-4.4 mmol/L; 1.6-4.2 mmol/L; 1.6-4.4 mmol/L), creatinine (36-68 μmol/L; 34-66 μmol/L; 36-68 μmol/L), and UA (122-297 μmol/L; 129-327 μmol/L; 147-376 μmol/L) for trimesters 1, 2, and 3, respectively, were established. These newly established reference intervals will be valuable for the detection and monitoring of kidney disease in pregnancy.