Reference intervals developed from data for hospitalized patients: computerized method based on combination of laboratory and diagnostic data

1994 ◽  
Vol 40 (12) ◽  
pp. 2209-2215 ◽  
Author(s):  
T Kouri ◽  
V Kairisto ◽  
A Virtanen ◽  
E Uusipaikka ◽  
A Rajamäki ◽  
...  
Keyword(s):  
Mean Corpuscular Volume ◽  
Age Groups ◽  
Hemoglobin Concentration ◽  
Reference Intervals ◽  
Hospitalized Patients ◽  
Healthy Individuals ◽  
Reference Limits ◽  
Health Related ◽  
Final Group

Abstract We utilized the databases of a hospital information system to select for determination of reference values various individual hospitalized patients on the basis of their diagnoses at discharge. The nonparametric 2.5-97.5% "health-related" reference intervals were calculated for hemoglobin concentration, mean corpuscular volume (MCV), and erythrocyte count for both sexes. After excluding patients with diseases possibly affecting erythrocyte variables, we obtained a final group of 1786 women and 1450 men, ages 20-65 years, who were studied in age groups of 20-30, 30-45, 45-55, and 55-65 years. The upper reference limits of the MCV results obtained from hospitalized patients were higher than those produced conventionally from healthy individuals, as would be intuitively suggested by clinical experience. This method, based on selection by diagnosis, could be applicable to various analytes measured in hospital laboratories, provided sufficient data are available as databases.

scholarly journals Determination of indirect reference intervals of vitamin B12 for outpatients admitted to primary healthcare centers

2020 ◽  
Vol 44 (1) ◽  
pp. 11-16
Author(s):  
Esin Avci ◽  
Diler Aslan
Keyword(s):  
Vitamin B12 ◽  
Primary Healthcare ◽  
Clinical Chemistry ◽  
Age Groups ◽  
Vitamin B12 Deficiency ◽  
Reference Intervals ◽  
Microcytic Anemia ◽  
Reference Limits ◽  
B12 Deficiency

Abstract Background Vitamin B12 deficiency is still an important nutritional problem worldwide. There is no consensus on the reference intervals (RIs) for vitamin B12. In order to establish vitamin B12 RIs, we used the database obtained from a primary healthcare organization and estimated region-specific intervals. Methods Vitamin B12 results were collected from our laboratory information system (LIS) between January 2014 and July 2014. We excluded the results of the individuals who had megaloblastic and microcytic anemia. After outlier detection and exclusion, we estimated the RIs of the “1–12, 13–18, 19–64 and 65 +” age groups according to the International Federation of Clinical Chemistry (IFCC) method. Statistical differences were examined between groups. Results The reference limits and 90% confidence intervals (CIs) (n = 14,748, 3790 male, age: 1–96; 10,958 female, age: 1–115) were estimated with 90% CIs as 106 (104–107)–393 (391–395) pmol/L. We also estimated the reference limits of the “1–12, 13–18, 19–64 and 65 +” age groups to be 127–459, 108–398, 106–384 and 104–426 pmol/L, respectively. There was no difference between genders in all age groups. Conclusions Both the lower and upper limits of the estimated RIs were found to be lower than the reference limits recommended by the manufacturer. Our findings revealed that the RIs of vitamin B12 should be given for the “1–12, 13–18, 19–64 and 65 +” age groups separately. The big data obtained from laboratories should be used for the determination of its population health status. As our population is composed of outpatients, the estimated vitamin B12 RIs may establish the basic information for the examination of our population for vitamin B12 deficiency.

scholarly journals Inaccuracy in automated measurement of hematocrit and corpuscular indices in the presence of severe hyperglycemia

Blood ◽  
1981 ◽  
Vol 57 (6) ◽  
pp. 1065-1067 ◽  
Author(s):  
JA Strauchen ◽  
W Alston ◽  
J Anderson ◽  
Z Gustafson ◽  
LF Fajardo
Keyword(s):  
Blood Glucose ◽  
Mean Corpuscular Volume ◽  
Hemoglobin Concentration ◽  
Mean Corpuscular Hemoglobin ◽  
Corpuscular Volume ◽  
Automated Measurement ◽  
Mean Corpuscular Hemoglobin Concentration ◽  
Corpuscular Hemoglobin ◽  
Hyperosmolar Glucose

Abstract Because we recently observed two patients with severe diabetic hyperglycemia and spuriously elevated electronically determined hematocrit and mean corpuscular volume (MCV), we investigated the effect of hyperglycemia on two popular automated hematology systems, the Coulter S and Ortho ELT-8. Marked hyperglycemia (blood glucose 800-- 2000 mg/dl) caused consistent overestimation of the electronically determined MCV compared to that derived from a simultaneous spun microhematocrit. The resultant overestimation and underestimation, respectively, of the derived values for hematocrit and mean corpuscular hemoglobin concentration may be clinically misleading. The mechanism of MCV elevation in hyperglycemia appears to be swelling of hyperosmolar glucose “loaded” erythrocytes when diluted into “isotonic” counting medium. This effect is readily circumvented by determination of a spun microhematocrit.

Determination of Protein C Antigen Levels in Hospitalized Patients with Blood Coagulative Defects

2021 ◽  
Vol 2 (1) ◽  
pp. 1-04
Author(s):  
George Zhu
Keyword(s):  
Plasma Protein ◽  
Protein C ◽  
Activated Protein C ◽  
Protein S ◽  
Promyelocytic Leukemia ◽  
Hospitalized Patients ◽  
Cancer Cell Proliferation ◽  
Healthy Individuals ◽  
Acute Leukemias

Protein C, a vitamin K-dependent anticoagulant serine protease, is involved in blood coagulation. Activated protein C inactivates Va and VIIIa in purified protein systems and stimulates fibrinolysis by indirectly increasing the level of circulating plasminogen activator. In this process, protein S serve as an important factor for activated protein C. In recent years, excess protein S drives cancer cell proliferation and cell survival through oncogenic receptor Axl (Anexelekto). We determined changes of plasma protein C antigen by using rocket immunoassay both in 50 healthy individuals and 103 distinct hospitalized patients. In healthy individuals protein C antigen(PC:Ag) ranges o.6439- 1.4752 µ/ml. The results showed that plasma protein C antigen was considerably high in 22 diabetes mellitus. In contrast, the PC:Ag was significantly decreased in 19 liver cirrhosis(p< 0.001) and in closely line with serum albumin levels(p< 0.05). In 31 acute leukemias, on the average, there was slightly lower values in PC:Ag, and accompanied with the distribution of significant decrease of PC:Ag values in 5 FAB M5 subtype and in 9 hyperleukocytic leukemias. However, the 3 acute promyelocytic leukemia (APL) with overt laboratory criteria of disseminated intravascular coagulation (DIC) had protein C concentration no lower than the remaining 2 patients with infectious DIC, which suggested the coagulopathy in APL might be due to mechanisms different from other forms of DIC.

Age-Specific Reference Intervals for PT, aPTT, Fibrinogen and Thrombin Time for Parturient Women

2019 ◽  
Vol 119 (06) ◽  
pp. 894-898
Author(s):  
Gao-Ming Zhang ◽  
Wei Zhang ◽  
Guo-Ming Zhang
Keyword(s):  
Age Groups ◽  
Reference Intervals ◽  
Activated Partial Thromboplastin Time ◽  
Blood Levels ◽  
Specific Reference ◽  
Thrombin Time ◽  
Healthy Individuals ◽  
Medical Decisions ◽  
Large Dataset ◽  
Upper Limit

Background Parturient women are healthy individuals who require special consideration. Parturient women are considered to be in a hyper-coagulable state. For example, the fibrinogen (FIB) levels are often higher than the upper limit of normal reference intervals (RIs) in parturient women than in non-parturient healthy individuals (2–4 g/L). Objective The aim of this study is to establish the RIs of pro-thrombin time (PT), activated partial thromboplastin time (aPTT), FIB levels and thrombin time (TT) for parturient women. Materials and Methods Blood levels of PT, aPTT, FIB and TT were assayed on an ACL TOP 700 automatic coagulation analyser using plasma samples from 10,472 parturient women. Outlier results were excluded by using Tukey's test. The RIs were calculated by the Clinical and Laboratory Standards Institute C28-A3 guideline. Results The RIs of PT, aPTT, FIB and TT were 8.7 to 12.1 seconds (8.7–12.2 seconds for 16–20 years old, 8.7–12.1 second for 21–25 years old, 8.6–12.0 second for 26–30 years old, 8.7–12.0 second for 31–35 years old, 8.7–12.6 second for 36–40 years old and 8.8–12.2 second for 41 years old), 22.9 to 42.3 seconds, 1.98 to 5.82 g/L and 9.9 to 16.7 seconds, respectively. PT levels were found to be positively associated with aging. Conclusion The above-established age-specific RIs, defined by using a large dataset, may assist clinicians in making accurate medical decisions. This was the first study in which the RIs of PT, aPTT, FIB and TT were established for parturient women in different age groups.

scholarly journals Clinical thresholds for diagnosing iron deficiency: comparison of functional assessment of serum ferritin to population based centiles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gorkem Sezgin ◽  
Paul Monagle ◽  
Tze Ping Loh ◽  
Vera Ignjatovic ◽  
Monsurul Hoq ◽  
...  
Keyword(s):  
Iron Deficiency ◽  
Serum Ferritin ◽  
Age Groups ◽  
Hemoglobin Concentration ◽  
Population Based ◽  
Reference Intervals ◽  
Deficiency Anemia ◽  
Distribution Width ◽  
Iron Deficient ◽  
Lower Limits

Abstract Low serum ferritin is diagnostic of iron deficiency, yet its published lower cut-off values are highly variable, particularly for pediatric populations. Lower cut-off values are commonly reported as 2.5th percentiles, and is based on the variation of ferritin values in the population. Our objective was to determine whether a functional approach based on iron deficient erythropoiesis could provide a better alternative. Utilizing 64,443 ferritin test results from pediatric electronic health records, we conducted various statistical techniques to derive 2.5th percentiles, and also derived functional reference limits through the association between ferritin and erythrocyte parameters: hemoglobin, mean corpuscular volume, mean cell hemoglobin concentration, and red cell distribution width. We find that lower limits of reference intervals derived as centiles are too low for clinical interpretation. Functional limits indicate iron deficiency anemia starts to occur when ferritin levels reach 10 µg/L, and are largely similar between genders and age groups. In comparison, centiles (2.5%) presented with lower limits overall, with varying levels depending on age and gender. Functionally-derived limits better reflects the underlying physiology of a patient, and may provide a basis for deriving a threshold related to treatment of iron deficiency and any other biomarker with functional outcomes.

Determination of reference limits: statistical concepts and tools for sample size calculation

2014 ◽  
Vol 52 (12) ◽  
Author(s):  
Stefan Wellek ◽  
Karl J. Lackner ◽  
Christine Jennen-Steinmetz ◽  
Iris Reinhard ◽  
Isabell Hoffmann ◽  
...  
Keyword(s):  
Sample Size ◽  
Diagnostic Marker ◽  
Parametric Method ◽  
Sample Size Calculation ◽  
Reference Intervals ◽  
Healthy Population ◽  
Reference Limits

AbstractReference limits are estimators for ‘extreme’ percentiles of the distribution of a quantitative diagnostic marker in the healthy population. In most cases, interest will be in the 90% or 95% reference intervals. The standard parametric method of determining reference limits consists of computing quantities of the form

Age-, sex-, and race-related differences in myoglobin concentrations in the serum of healthy persons.

1980 ◽  
Vol 26 (13) ◽  
pp. 1864-1868 ◽  
Author(s):  
I W Chen ◽  
R David ◽  
H R Maxon ◽  
M Sperling ◽  
E A Stein
Keyword(s):  
Black Women ◽  
Black Men ◽  
White Women ◽  
Age Groups ◽  
White Men ◽  
Reference Intervals ◽  
Creatinine Ratio ◽  
Healthy Individuals ◽  
Female Population ◽  
Serum Myoglobin

Abstract A radioimmunoassay was used to study the relation of race, sex, and age to serum myoglobin concentrations in ostensibly healthy individuals: 75 white men, 76 white women, 75 black men, and 66 black women, ranging in age from 20 to 85 years. Mean serum myoglobin values were significantly higher in men than in women in both races (35 vs 31 microgram/L for whites and 44 vs 29 microgram/L for blacks). Black men had higher values than white men, but no corresponding difference was observed in the female population. Except for the group of black men, which consistently had the highest values for serum myoglobin, values were always higher for the older groups (greater than or equal to 50 years) than the younger, irrespective of race or sex. Serum myoglobin and age were significantly and directly correlated only among white men (r = 0.3408 p &lt; 0.01, n = 75). If results were expressed as a myoglobin/creatinine ratio, the distinctions by race, sex, and age were partly eliminated. Reference intervals for serum myoglobin, expressed both ways, are given for different race, sex, and age groups.

Recommendation for the review of biological reference intervals in medical laboratories

2016 ◽  
Vol 54 (12) ◽  
Author(s):  
Joseph Henny ◽  
Anne Vassault ◽  
Guilaine Boursier ◽  
Ines Vukasovic ◽  
Pika Mesko Brguljan ◽  
...  
Keyword(s):  
Expert Panel ◽  
Clinical Chemistry ◽  
Simple Procedure ◽  
Reference Population ◽  
Reference Intervals ◽  
Medical Laboratories ◽  
Reference Limits ◽  
Original Procedure ◽  
Selection Of

AbstractThis document is based on the original recommendation of the Expert Panel on the Theory of Reference Values of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), updated guidelines were recently published under the auspices of the IFCC and the Clinical and Laboratory Standards Institute (CLSI). This document summarizes proposals for recommendations on: (i) The terminology, which is often confusing, noticeably concerning the terms of reference limits and decision limits. (ii) The method for the determination of reference limits according to the original procedure and the conditions, which should be used. (iii) A simple procedure allowing the medical laboratories to fulfill the requirements of the regulation and standards. The updated document proposes to verify that published reference limits are applicable to the laboratory involved. Finally, the strengths and limits of the revised recommendations (especially the selection of the reference population, the maintenance of the analytical quality, the choice of the statistical method used…) will be briefly discussed.

scholarly journals Reference intervals for hemoglobin and mean corpuscular volume in an ethnically diverse community sample of Canadian children 2 to 36 months

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jemila S. Hamid ◽  
Eshetu G. Atenafu ◽  
Cornelia M. Borkhoff ◽  
Catherine S. Birken ◽  
Jonathon L. Maguire ◽  
...  
Keyword(s):  
Confidence Intervals ◽  
Mean Corpuscular Volume ◽  
Community Sample ◽  
Age Groups ◽  
Ethnically Diverse ◽  
Reference Interval ◽  
Reference Intervals ◽  
Corpuscular Volume ◽  
Link Type ◽  
Diverse Community

Abstract Objective To establish reference intervals for hemoglobin and mean corpuscular volume (MCV) in an ethnically diverse community sample of Canadian children 36 months and younger. Methods We collected blood samples from young children at scheduled primary care health supervision visits at 2 weeks, 2, 4, 6, 9, 12, 15, 18, 24, and 36 months of age. Samples were analyzed on the Sysmex XN-9000 Hematology Analyzer. We followed the Clinical and Laboratory Standards Institute guidelines in our analysis. Data were partitioned by sex and also combined. We considered large age partitions (3 and 6 months) as well as monthly partitions. Reference intervals (lower and upper limits) and 90% confidence intervals were calculated. Results Data from 2106 children were included. The age range was 2 weeks to 36 months, 46% were female, 48% were European and 23% were of mixed ethnicity. For hemoglobin, from 2 to 36 months of age, we found a wide reference interval and the 90% confidence intervals indicated little difference across age groups or according to sex. For MCV, from 2 to 7 months of age there was considerable decrease in the reference interval, which was lowest during the second year of life, followed by a slight increase in the last months of the third year of life. Conclusion These findings suggest adoption of a single hemoglobin reference interval for children 2–36 months of age. Further studies in children under 4 months of age are needed. Trial registration TARGet Kids! cohort is registered at ClinicalTrials.gov. www.clinicaltrials.gov. Identifier: NCT01869530.

scholarly journals Inaccuracy in automated measurement of hematocrit and corpuscular indices in the presence of severe hyperglycemia

Blood ◽  
1981 ◽  
Vol 57 (6) ◽  
pp. 1065-1067
Author(s):  
JA Strauchen ◽  
W Alston ◽  
J Anderson ◽  
Z Gustafson ◽  
LF Fajardo
Keyword(s):  
Blood Glucose ◽  
Mean Corpuscular Volume ◽  
Hemoglobin Concentration ◽  
Mean Corpuscular Hemoglobin ◽  
Corpuscular Volume ◽  
Automated Measurement ◽  
Mean Corpuscular Hemoglobin Concentration ◽  
Corpuscular Hemoglobin ◽  
Hyperosmolar Glucose

Because we recently observed two patients with severe diabetic hyperglycemia and spuriously elevated electronically determined hematocrit and mean corpuscular volume (MCV), we investigated the effect of hyperglycemia on two popular automated hematology systems, the Coulter S and Ortho ELT-8. Marked hyperglycemia (blood glucose 800-- 2000 mg/dl) caused consistent overestimation of the electronically determined MCV compared to that derived from a simultaneous spun microhematocrit. The resultant overestimation and underestimation, respectively, of the derived values for hematocrit and mean corpuscular hemoglobin concentration may be clinically misleading. The mechanism of MCV elevation in hyperglycemia appears to be swelling of hyperosmolar glucose “loaded” erythrocytes when diluted into “isotonic” counting medium. This effect is readily circumvented by determination of a spun microhematocrit.

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