Interpretation Of Laboratory Results Research Articles

Hematological and biochemical laboratory reference intervals for Zimbabwean adolescents.

Reference intervals are used as an aid in the interpretation of laboratory results. Most developing countries do not have reference intervals specific to adolescents. This study was aimed at establishing hematological and biochemical reference intervals for adolescents aged ≥ 12 years to < 18 years. A community based, cross sectional study was conducted using the multistage sampling technique. Participants were enrolled from the UZ-UCSF research study catchment areas of Harare, Chitungwiza, and Mutoko. Samples were transported for analysis at the UZ-UCSF Central Laboratory under recommended conditions. The data analysis presented in this paper is for 302 adolescents aged ≥ 12 to < 18. Non-parametric statistical methods were used to estimate the 95% reference limits for the hematological and biochemical parameters, with the lower limit defined as the 2.5 percentile and the upper limit defined as the 97.5 percentile of the distribution. A total of 302 adolescents were included. Results show significant differences between males and females in hematological parameters except platelets, eosinophils, basophils, and red cell distribution width. The biochemical parameters which showed significant differences between males and females were phosphate, ALP, ALT, AST, GGT, and lipase. Hematological indices and liver function tests differ significantly by gender and this should be considered when defining normal intervals.

Coverage intervals for trace elements in human scalp hair are site specific

Coverage intervals for trace elements in human scalp hair commonly provide the basis for interpreting laboratory results and also in comparative decision-making processes regarding exposure risk assessment. This short communication documents, by some examples, that those computed for human hair are to be considered site specific, as they reflect local environmental conditions; also each geographic area has a typical profile of hair elemental composition of its inhabitants. Therefore, the levels of trace elements in hair are not strictly comparable between different areas of the world. This issue is particularly relevant when identification of anomalous environmental exposures are requested or even in detecting physiological disorders.

Development of paediatric biochemistry centile charts as a complement to laboratory reference intervals

Age-specific paediatric reference intervals are used in interpretation of laboratory results. However, interpretation may be problematic when a child just crosses an age bracket and the difference between the original and the subsequent age-specific reference interval is large. Moreover, details about the physiological changes with age may be masked. For the 12 months ending 30 September 2013, results of 16 common clinical biochemistry tests of ambulatory paediatric patients aged 0-19, requested by primary care physicians, were retrospectively collected in a large pathology service, and used to construct smoothed centile charts using a penalised maximum likelihood method. From the developed centile charts, the concentrations of sodium, bicarbonate, creatinine, urate, total protein, and albumin all increased with increasing age of the children. In contrast, the concentrations of potassium, chloride, anion gap, calcium, phosphate and lactate dehydrogenase decreased with increasing age of the children. Changes in the concentrations of urea, alkaline phosphatase, glucose, and total cholesterol varied by age. Generally, the boys and girls shared similar trend patterns until 10-15 years of age, when variations in the age of onset of puberty and development caused the trends of some biochemical measures to differ. The paediatric biochemistry centile charts are intuitive tools to use. They complement age-specific reference intervals in the tracking, interpretation and discussion of laboratory results. They also enhance the understanding of underlying physiological changes in biochemistry in children.

Biological variation of immunoglobulin heavy chain-light chain pairs in serum

BackgroundAssays for immunoglobulin heavy chain-light chain (HLC) pairs called Hevylite® have recently been developed. These assays can be useful in patients with hard to interpret serum protein electrophoresis peaks. Measurement of the biological variation of clinical laboratory tests can help clinicians better interpret laboratory results. MethodsSerum samples were collected from 15 healthy donors and assayed with IgAκ, IgAλ, IgGκ and IgGλ Hevylite. The coefficients of the within-subject and between-subject biological variation, index of individuality (II), number of samples (n) required to determine the homeostatic setting points (HSP) and reference change values (RCV) were calculated. ResultsThe coefficients of the within-subject biologic variation were all less than the between-subject biological variation. The II for all the assays and their κ/λ ratios were near or <0.6. The RCV ranged from 17 to 41%. The number of measurements to determine the HSP for an individual was 1 for the HLC ratios and between 2 and 9 for the individual isoforms. ConclusionsII indicates it is better to use the patient's individual results rather than population based reference values, fewer measurements are required to determine the HSP for the HLC ratios than the individual isoforms and the RCV can now be used to aid in interpretation.

Analysis of queries from nurses to the South African National HIV &amp; TB Health Care Worker Hotline

Background. Since 2008, the Medicines Information Centre (MIC) has run the South African National HIV &amp; TB Health Care Worker Hotline which provides free information on patient treatment to all healthcare workers in South Africa. With the introduction of nurse-initiated management of antiretroviral therapy (NIMART) in the public sector, the need for easy access to HIV and tuberculosis (TB) information has increased, especially among nurses. The hotline aims to provide this, most importantly to nurses in rural areas, where clinical staff often have little access to peer review.Objective. To describe the queries received from nurses by the hotline between 1 March and 31 May 2012 and identify problem areas and knowledge gaps where nurses may require further training.Methods. All queries received from nurses during the study period were analysed. An experienced information pharmacist reviewed all queries to identify knowledge gaps.Results. During the study period, the hotline received a total of 1 479 HIV- and TB-related queries from healthcare workers. Of these, 386 were received from nurses, of which 254 (66%) were NIMART-trained. The most common query subtopic was initiating antiretroviral therapy (ART) (20%), followed by adverse drug reactions (18%). The most common knowledge gap identified was the ability to interpret laboratory results before initiating ART (10%).Discussion. We conclude that the hotline is providing clinical help to an increasing number of nurses on the topic of treating HIV and TB throughout South Africa. In addition, queries directed to the hotline may assist in identifying knowledge gaps for the further training of nurses.

Analysis of queries from nurses to the South African National HIV &amp; TB Health Care Worker Hotline

Background. Since 2008, the Medicines Information Centre (MIC) has run the South African National HIV &amp; TB Health Care Worker Hotline which provides free information on patient treatment to all healthcare workers in South Africa. With the introduction of nurse-initiated management of antiretroviral therapy (NIMART) in the public sector, the need for easy access to HIV and tuberculosis (TB) information has increased, especially among nurses. The hotline aims to provide this, most importantly to nurses in rural areas, where clinical staff often have little access to peer review. Objective. To describe the queries received from nurses by the hotline between 1 March and 31 May 2012 and identify problem areas and knowledge gaps where nurses may require further training. Methods. All queries received from nurses during the study period were analysed. An experienced information pharmacist reviewed all queries to identify knowledge gaps. Results. During the study period, the hotline received a total of 1 479 HIV- and TB-related queries from healthcare workers. Of these, 386 were received from nurses, of which 254 (66%) were NIMART-trained. The most common query subtopic was initiating antiretroviral therapy (ART) (20%), followed by adverse drug reactions (18%). The most common knowledge gap identified was the ability to interpret laboratory results before initiating ART (10%). Discussion. We conclude that the hotline is providing clinical help to an increasing number of nurses on the topic of treating HIV and TB throughout South Africa. In addition, queries directed to the hotline may assist in identifying knowledge gaps for the further training of nurses.

No asymptomatic malaria parasitaemia found among 108 young children at one health facility in Dar es Salaam, Tanzania

BackgroundAsymptomatic malaria parasitaemia has been reported in areas with high malaria transmission. It may serve as a reservoir for continued transmission, and furthermore complicates diagnostics, as not all individuals with a positive malaria test are necessarily ill due to malaria, although they may present with malaria-like symptoms. Asymptomatic malaria increases with age as immunity to malaria gradually develops. As mortality and morbidity of malaria is higher among younger children it is important to know the prevalence of asymptomatic malaria parasitaemia in this population in order to interpret laboratory results for malaria correctly.MethodsA total of 108 children that had neither been treated for malaria nor had a fever the previous four weeks were recruited consecutively at a maternal and child health clinic (MCHC) in Dar es Salaam, Tanzania. A rapid diagnostic test (RDT) for malaria and dried blood spot (DBS) on filter paper were taken from each child. Social and clinical data were recorded. DNA was extracted from the DBS of study participants by a method using InstaGene™ matrix. PCR targeting the Plasmodium mitochondrial genome was performed on all samples.ResultsMedian age was 4.6 months (range 0.5-38). All the RDTs were negative. PCR was negative for all study subjects.ConclusionThe study suggests that asymptomatic malaria may not be present in apparently healthy children up to the age of three years in Dar es Salaam, Tanzania. However, because of the small sample size and low median age of the study population, the findings cannot be generalized. Larger studies, including higher age groups, need to be done to clarify whether asymptomatic malaria parasitaemia is present in the general population in the Dar es Salaam area.

Interpreting Laboratory Results in Transgender Patients on Hormone Therapy

BackgroundClinical guidelines recommend laboratory monitoring of transgender persons on cross-sex hormone therapy, but gender-specific reference intervals leave clinicians with the dilemma of deciding what is “normal” for each patient. The goal of this study was to identify consistent changes in measurands with hormone therapy and determine which reference interval is appropriate. MethodsLaboratory data were abstracted from the medical records of 55 male-to-female patients on hormone therapy and compared with 20 male and 20 female nontransgender subjects. ResultsHemoglobin, hematocrit, and low-density lipoprotein resembled female values (P < .005), while alkaline phosphatase, potassium, and creatinine resembled male values (P < .05). Triglycerides were higher (P < .005) than either the male or female groups. The remainder of the measurands showed no differences. ConclusionsUse of correct reference intervals in interpreting laboratory results reduces the risk of testing-related diagnostic error. Preliminary data suggest that new reference intervals need to be established for transgender patients.

Factor XIII Deficiency: An Update

Confirmation of suspected congenital factor XIII (FXIII) deficiency still represents a diagnostic challenge in the field of rare bleeding disorders. Because of the lack of awareness and difficulties associated with timing of blood sampling, FXIII laboratory assays, and interpretation of laboratory results, diagnoses of FXIII deficiency are still missed all over the world with potentially fatal consequences from severe bleeding complications. Better knowledge of FXIII biochemical properties and function and understanding of the principles and limitations of FXIII laboratory assays can prevent missed diagnoses, and patients will benefit from better care. This review gives a detailed overview and update about congenital FXIII deficiency, its epidemiology, and molecular genetics. It highlights the importance of newer specific FXIII assays and their principles to avoid any missed diagnosis of FXIII deficiency. This review also gives an update on the therapeutic options for patients suffering from this rare but life-threatening disease.

Planned variation in preanalytical conditions to evaluate biospecimen stability in the National Children’s Study (NCS)

Preanalytical conditions encountered during collection, processing, and storage of biospecimens may influence laboratory results. The National Children's Study (NCS) is a planned prospective cohort study of 100,000 families to examine the influence of a wide variety of exposures on child health. In developing biospecimen collection, processing, and storage procedures for the NCS, we identified several analytes of different biochemical categories for which it was unclear to what extent deviations from NCS procedures could influence measurement results. A pilot study was performed to examine effects of preanalytic sample handling conditions (delays in centrifugation, freezing delays, delays in separation from cells, additive delay, and tube type) on concentrations of eight different analytes. A total of 2825 measurements were made to assess 15 unique combinations of analyte and handling conditions in blood collected from 151 women of childbearing age (≥ 20 individuals per handling condition). The majority of analytes were stable under the conditions evaluated. However, levels of plasma interleukin-6 and serum insulin were decreased in response to sample centrifugation delays of up to 5.5 h post-collection (p<0.0001). In addition, delays in freezing centrifuged plasma samples (comparing 24, 48 and 72 h to immediate freezing) resulted in increased levels of adrenocorticotropic hormone (p=0.0014). Determining stability of proposed analytes in response to preanalytical conditions and handling helps to ensure high-quality specimens for study now and in the future. The results inform development of procedures, plans for measurement of analytes, and interpretation of laboratory results.

Serum biochemical and hematological reference values for lactating buffaloes

Serum biochemical and hematological reference values are used to establish normality and to diagnose disease and physiological alterations. Up till now, there are no reference values for different blood biochemical and hematological variables in buffaloes, consequently the current study aimed to establish those reference values in non-pregnant lactating buffaloes. In total, 202 lactating buffaloes (5–10 years old) were examined at buffalo farms that belong to Assiut Governorate, Egypt. Seventy buffaloes did not meet the selection criteria and were excluded from study. The remaining buffaloes (N = 132) were included in the study. A total of 55 hematological and serum biochemical constituents were measured in blood of lactating buffaloes. Mean reference values, reference intervals (2.5 and 97.5 percentiles) and their 90 % confidence intervals, for the measured hematological and serum biochemical constituents were statistically calculated. It could be concluded that reference values for hematological and serum biochemical constituents in lactating buffaloes were estimated in this study, these values will be helpful in interpreting laboratory results, diagnosis of diseases, and checking the health status of non-pregnant lactating buffaloes.

Diversity of viruses detected by deep sequencing in pigs from a common background

Although advances in nucleic acid sequencing have enabled the discovery of many infectious agents, challenges remain for scientists and veterinary diagnosticians trying to design animal studies with a minimum of variables and to interpret laboratory results. To evaluate pyrosequencing technology as a potential screening method to estimate the virome in pigs, fecal samples were collected from 4 pigs out of a group of 175 that had been raised together since birth. A number of viruses were detected, demonstrating the application of this technology to determine the background "noise" in the pigs. However, pyrosequencing also demonstrated the diversity of viruses within a group of animals and how that can confound experimental design and obscure a definitive diagnosis.

Establishment of reference intervals of 24 chemistries in apparently healthy adult Han population of Northern China

BackgroundThe availability of reference intervals is essential for physicians to interpret laboratory results. Most of our laboratory reference intervals are derived from data on the foreign population. We have studied the reference intervals of 24 common laboratory biochemical tests in an apparently healthy adult Han population of Northern China. Methods1364 healthy individuals between 20 and 79years old were recruited. 24 different chemical analytes were tested by the Roche Modular P 800 analyzer. We stratified the populations by gender and age through applying exclusion criteria, and the reference intervals were obtained by statistical analysis. ResultsReference intervals for 24 common analytes in a gender and age appropriate adult Han population of Northern China are reported. ConclusionOur study provides adequate laboratory data on reference intervals. The results emphasize the significance of establishing population-based reference intervals for a clinical laboratory.

Preanalytic conditions of the C-reactive protein are of paramount importance to use as a predictor of cardiovascular disease in clinical practice

We read the article by Wu et al. [1] about of the intra-individual variability of high-sensitivity C-reactive protein (hsCRP) in a cohort of Chinese adults. They recruited a large population (44,140 males and 12,078 females) inwhich blood samples were obtained during morning. The authors conclude that the age and gender are factors that influenced the hsCRP level. However, in the present article we saw an additional potential limitation of the study: they have not determined the hsCRP along a 24-hour period to eliminate the possible influence of circadian rhythms. Many epidemiological studies have demonstrated that hsCRP, a biomarker of inflammation, is an important prognostic factor for the future occurrence of major cardiovascular events, both in patients with known cardiovascular disease and apparently in healthy subjects [2,3]. The 2009 National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines included and endorsed the use of hsCRP as a novel means by which to identify individuals who are at risk for vascular disease [4]. Circulating biomarkers are subject to variability arising from sampling procedures andbiologic variation, and this variabilitymust be determined and adjusted for in the interpretation of laboratory results. Diurnal variation may be an important source of heterogeneity or bias, and standardization for sampling time may be important in populationbased studies, as well as, in using these variables for additional coronary heart disease risk prediction in individuals [5–8]. The available data on diurnal variations of hsCRP levels in healthy subjects are few and controversial. We have demonstrated absence of diurnal variation of hsCRP levels, when blood samples were collected at 9:00 AM (light period) and 2:00 AM (dark period) from 70 healthy subjects [9]. Previously, Meier-Ewert and colleagues found no diurnal variation in hsCRP samples that were taken hourly from 13 healthy subjects [10]. In other study of hsCRP, D-dimer, tissue plasminogen activator, and von Willebrand factor in a middle-aged population showed diurnal variation as high as 34% in hsCRP, with maximum hsCRP levels observed at 3:00 PM. However, that study was limited in that hsCRP was measured between 9:00 AM and 10:00 PM [11]. Moreover, recently Koc and colleagues [12] demonstrated a variation of 86% of hsCRP in 30 subjects who had normal coronary arteries at 6hour intervals over 24-hour period. Wu et al. have discussed in their manuscript that the age and environmental variables, such as lipid levels, blood pressure, obesity and diabetesmellitus can contribute to the variation of hsCRP [1,13]. However, with the items mentioned above, we believe that the diurnal variation should be taken into account as a control variable in multivariate regression models. In summary, hsCRP represents the most extensively studiedproinflammatorymolecule, but additional effort is requiredon the part of the investigators to manage standardization of methodology and to determine cost-effective timing and frequency of measurements. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology (Shewan and Coats 2010;144:1–2).

Diabetes Care Practice Patterns of Recent Pharmacy Graduates

Purpose: The objective of this project was to determine the amount and type of clinical skills and diabetes education provided by recent pharmacy school graduates. Methods: Six hundred and one graduates were e-mailed a link to an online survey. Subjects were asked to report how frequently they either educate patients on diabetes self-care activities or perform diabetes-related patient care skills and to rate their ability to do so as poor, fair, good, or excellent. Results: Data from 155 (25.8%) respondents were analyzed. The most commonly reported clinical activity was changing medication, followed by interpreting blood glucose patterns, medication management therapy, and interpreting laboratory results. Subjects reported educating patients more on the signs and symptoms of hypoglycemia, blood glucose monitoring, and diet information relative to other topics. The majority of subjects rated their skills as good or excellent. Conclusion: Pharmacists reported the most commonly performed diabetes-related clinical skill was changing medication and they most often educate patients about hypoglycemia and blood glucose monitoring. Subjects, who rated themselves poor/fair in these skills, preferred active learning strategies to enhance their ability.

Should adult patients be routinely tested for heritable thrombophilia after an episode of venous thromboembolism?

The clinical usefulness of laboratory testing of adult patients with venous thromboembolism (VTE) for heritable thrombophilia needs to be critically evaluated. At present, some clinicians use testing to identify patients at higher risk of recurrence (who may benefit from an extended period of anticoagulation beyond the usual 3-6months) and their relatives at risk of a first VTE episode. As prevalence of heritable thrombophilia is related to age and ethnic origin, the pretest probability of detecting heritable thrombophilia may be low in unselected populations. Interpretation of laboratory results may not be straightforward. Apparent deficiencies of a natural anticoagulant may be due to acute thrombosis and "consumption", concomitant therapy with heparin and/or warfarin and other clinical factors. The predictive value of recurrent VTE conferred by the most common types of heritable thrombophilia (factor V Leiden and the G20210A prothrombin mutation) is limited. Risk of recurrence associated with deficiencies of a natural anticoagulant is less certain due to their rarity. Clinical risk factors (eg, the presence or otherwise of provoking factor(s) and whether or not the risk factor for VTE is reversible or permanent) appear to be the most important predictors of VTE recurrence. Duration of anticoagulation should be determined by clinical risk factors rather than the presence, or otherwise, of heritable thrombophilia. The benefit of identifying relatives who are carriers of thrombophilia is uncertain, as VTE is a multifactorial disease resulting from the interaction of various risk factors, some well recognised and others as yet unknown.

The Kuwait Oil Fire Health Risk Assessment Biological Surveillance Initiative

An important environmental concern during the first Gulf War (Operation Desert Storm) was assessing exposures and potential health effects in U.S. forces exposed to the Kuwait oil fires. With only 3 weeks for planning, a Biological Surveillance Initiative (BSI) was developed and implemented for a U.S. Army unit. The BSI included blood and urine collections, questionnaire administration, and other elements during the predeployment, deployment, and post-deployment phases. Many BSI objectives were accomplished. Difficulties encountered included planning failures, loss of data and information, and difficulty in interpreting laboratory results. In order for biological surveillance initiatives to provide useful information for future deployments where environmental exposures may be a concern, meaningful, detailed, and realistic planning and preparation must occur long before the deployment is initiated.

265 UROLOGISTS AND THE PATIENT-CENTERED MEDICAL HOME

You have accessJournal of UrologyGeneral & Epidemiological Trends & Socioeconomics: Quality of Life1 Apr 2010265 UROLOGISTS AND THE PATIENT-CENTERED MEDICAL HOME John M. Hollingsworth and David C. Miller John M. HollingsworthJohn M. Hollingsworth More articles by this author and David C. MillerDavid C. Miller More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.325AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES One of the most widely-discussed delivery-system reforms is the medical home. At present, most models emphasize the need for primary care practices to manage comprehensively their patients' chronic care needs, but the medical home is in theory neutral with respect to the specialty of a patient's doctor. Therefore, it may be possible for urology practices to function as medical homes for patients with certain chronic conditions, including genitourinary (GU) cancers. Implementation of this model would require transferring some or all of the care for these conditions that primary care physicians (PCPs) currently provide to urologists and urology practices. To explore the feasibility of this approach, we estimated the implications of consolidating GU cancer follow-up care among the existing urology workforce. METHODS Using the 2007 National Ambulatory Medical Care Survey, we abstracted adult ambulatory visits to PCPs and urologists for 4 GU cancers (prostate, bladder, kidney, and testis). We first determined the amount of time that PCPs spent in direct (i.e., face-to-face contact) and indirect care (e.g., reviewing and interpreting laboratory results) for their established patients with these conditions. We then measured the time burden (in terms of annual 55-hour work weeks) associated with consolidating half of this follow-up care among the current supply of urologists. RESULTS In total, 26.8% of GU cancer-related visits were to PCPs, nearly all of which (95.2%) were for follow-up care. On average, PCPs spent 19.5 minutes with each established patient during a visit for a GU cancer. Summing across the 1.7 million return cancer visits to PCPs, this translated into 9,583 work weeks of direct care. PCPs spent an additional 1,551 work weeks in indirect care. Transferring 50% of this GU cancer care would generate nearly one additional work week for each actively-practicing urologist (Figure), a time commitment equivalent to expanding the urology workforce by 107 surgeons. CONCLUSIONS Our results demonstrate that consolidation of GU cancer follow-up is feasible. As such, urology practices would make logical medical homes for patients with these conditions. Ann Arbor, MI© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e104-e105 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information John M. Hollingsworth More articles by this author David C. Miller More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Grade Influences Blood Lactate Kinetics During Cross-Country Skiing

The purpose of this study was to examine the effects of level vs. graded skate skiing on capillary blood lactate (B(La)), heart rate (HR), oxygen consumption (V(O2)), and training intensity prescriptions. Eleven Nordic skiers completed 2 submaximal skate roller skiing treadmill protocols during which intensity was increased either by grade (G(inc)) or by speed (S(inc)). The protocols were compared for prethreshold BLa, HR, and V(O2) at lactate threshold (LT) and the HR/V(O2) relationship. Additionally, double-pole (primarily upper body) and skating (arms and legs combined) protocols were used to measure peak V(O2) and peak HR. Heart rate and V(O2) at LT were lower during G(inc) compared with S(inc) (154.9 +/- 6.8 b.min(-1) vs. 162.0 +/- 9.1 b.min(-1) and 46.3 +/- 2.8 ml.kg(-1).min(-1) vs. 49.1 +/- 1.6 ml.kg(-1).min(-1), respectively, both p < 0.01). Pre-threshold B(La) and the HR/V(O2) relationship were not different between the submaximal protocols. V(O2) and HRpeak were higher in skating compared with double poling (64.6 +/- 1.8 ml.kg(-1).min(-1) vs. 60.3 +/- 2.8 ml.kg(-1).min(-1), 192.6 +/- 5.8 b.min(-1) vs. 187.8 +/- 6.7 b.min(-1), respectively, both p < 0.01). Greater reliance on upper-body musculature during graded skiing and its associated lower aerobic capacity increases B(La) when compared with level skiing. The leftward shift in the B(La) vs. intensity curve during uphill skiing should be recognized to properly prescribe training intensity as well as interpret laboratory results.

Pitfalls in interpreting laboratory results

The results of laboratory tests are affected by the collection and handling of the specimen, the