Excessive diagnostic testing in acute kidney injury.

BACKGROUND: The patterns, performance characteristics, and yield of diagnostic tests ordered for the evaluation of acute kidney injury (AKI) have not been rigorously evaluated. METHODS: We characterized the frequency of AKI diagnostic testing for urine, blood, radiology, and pathology tests in all adult inpatients who were admitted with or developed AKI (N = 4903 patients with 5731 AKI episodes) during a single calendar year. We assessed the frequency of abnormal test results overall and by AKI stage. We manually reviewed electronic medical records to evaluate the diagnostic yield of selected urine, blood, and radiology tests. Diagnostic yield of urine and blood tests was determined based on whether an abnormal test affected AKI diagnosis or management, whereas diagnostic yield of radiology tests was based on whether an abnormal test resulted in a procedural intervention. In sensitivity analyses we also evaluated appropriateness of testing using prespecified criteria. RESULTS: Frequency of testing increased with higher AKI stage for nearly all diagnostic tests, whereas frequency of detecting an abnormal result increased for some, but not all, tests. Frequency of detecting an abnormal result was highly variable across tests, ranging from 0 % for anti-glomerular basement membrane testing to 71 % for urine protein testing. Many of the tests evaluated had low diagnostic yield. In particular, selected urine and blood tests were unlikely to impact AKI diagnosis or management, whereas radiology tests had greater clinical utility. CONCLUSIONS: In patients with AKI, many of the diagnostic tests performed, even when positive or abnormal, may have limited clinical utility.

Connect MM Registry: The Importance of Establishing Baseline Disease Characteristics.

BACKGROUND: Connect MM is the first and largest observational, noninterventional, prospective registry of patients newly diagnosed with multiple myeloma (NDMM) in the United States. It collects longitudinal data on patients within clinical practice including patients in clinical trials. PATIENTS AND METHODS: Of the 1513 patients enrolled, 1493 were protocol-eligible. RESULTS: Median age was 67 years, 81.9% (1223/1493) were Caucasian, and 57.2% (854/1493) were male. Of these patients, 26.5% (232/877) were International Staging System stage I, 34.9% (306/877) stage II, and 38.7% (339/877) stage III. Eastern Cooperative Oncology Group performance status of 0/1/2 were reported in 96.6% (1017/1053). Clonal plasma cells > 10% were found in 91.6% (1282/1399) of patients and M-component in 98.8% (1343/1359). Hypercalcemia was present in 7.3% (108/1481) of patients, serum creatinine > 2 mg/dL in 18.3% (271/1484), anemia in 45.1% (673/1493), and bone involvement in 76.7% (1143/1490). Of the 15 National Comprehensive Cancer Network (NCCN) recommended diagnostic tests, a median of 12 were performed. Lactate dehydrogenase assessment, serum free light chain ratio, and immunofixation were reported in 38.4% (574/1493), 62.1% (927/1493), and 66% (985/1493) of patients, respectively. Quantitative immunoglobulin, ß-2 microglobulin, and protein electrophoresis (serum or urine) were reported in 72.3% (1080/1493), 74.1% (1107/1493), and 78.0% (1164/1493) of patients, respectively. Bone marrow biopsy was reported in 92.2% (1376/1493), but conventional cytogenetic and fluorescence in situ hybridization analysis were reported in only 63.2% (944/1493) and 59.8% (893/1493) of patients, respectively. A high-risk cytogenetic profile (according to International Myeloma Working Group [IMWG] criteria) was found in 16.9% (253/1493). CONCLUSION: This analysis provides insight into the demographic and disease characteristics of NDMM patients in a range of clinical practices. Creating solid records of baseline patient disease characteristics using suggested NCCN diagnostic work-up and IMWG criteria provides a foundation for monitoring disease progression and response to treatment.

Optimization of utilization of serum protein analysis: role of the electronic medical record in promoting consultation by pathology.

Screening for monoclonal gammopathies is usually done by serum protein electrophoresis (SPEP) and serum free light chain tests. SPEP may be followed by immunofixation electrophoresis (IFE). IFE may be ordered by the treating physician or be at the discretion of the pathologist. We examined the appropriateness of IFE ordering by treating physicians and report on our findings, follow-up changes to the ordering process, and results of the change. We retrospectively analyzed the data from our laboratory from April 2009 through July 2012. In April 2009, 3 options for test ordering were available for the clinicians: SPEP with reflex IFE, SPEP only, and SPEP with IFE. This test ordering option was limited to SPEP with reflex IFE only in April 2010. We compared the rates of SPEP and IFE performed in the 2 periods (ie, April 2009 through April 2010 and May 2010 through July 2012). There was a substantial drop in the IFE/SPEP ratio from 0.47 to 0.21. Review of electronic medical records by the consultant pathologist was instrumental in improving the utilization and enhancing the value of pathology consultation. Possible impacts on laboratory costs, revenue, and overall health care are also presented.

Unexplained extreme hyperbilirubinemia among neonates in a multihospital healthcare system.

We report a series of neonates who developed a total serum bilirubin (TSB) >20mg/dL during a recent ten-year period in a multihospital healthcare system. The incidence of a TSB >20mg/dL fell after instituting a pre-hospital discharge bilirubin screening program in 2003/2004 (91.3 cases/10,000 births before vs. 72.4/10,000 after), but the incidence has subsequently remained unchanged. No specific cause for the hyperbilirubinemia was identified in 66% of (n=32) cases with a TSB >30 mg/dL or in 76% of (n=112) cases with a TSB 25.0-29.9 mg/dL. We hypothesized that hemolysis was a common contributing mechanism, but our review of hospital records indicated that in most instances these infants were not evaluated sufficiently to test this hypothesis. Records review showed maternal and neonatal blood types and direct antiglobulin testing were performed in >95% cases, but rarely were other tests for hemolysis obtained. In the ten-year period reviewed there were zero instances where erythrocyte morphology from a blood film examination or Heinz body evaluation by a pediatric hematologist or pathologist were performed. In 3% of cases pyruvate kinase was tested, 3% were evaluated by hemoglobin electrophoresis, 3% had a haptoglobin measurement, and 16% were tested for G6PD deficiency. Thus, determining the cause for hyperbilirubinemia in neonates remains a problem at Intermountain Healthcare and, we submit, elsewhere. As a result, the majority of infants with a TSB >25mg/dL have no specific causation identified. We speculate that most of these cases involve hemolysis and that the etiology could be identified if searched for more systematically. With this in mind, we propose a "consistent approach" to evaluating the cause(s) of hyperbilirubinemia among neonates with a TSB >25mg/dL.

Tests and expenditures in the initial evaluation of peripheral neuropathy.

BACKGROUND: Peripheral neuropathy is a common disorder in which an extensive evaluation is often unrevealing. METHODS: We sought to define diagnostic practice patterns as an early step in identifying opportunities to improve efficiency of care. The 1996-2007 Health and Retirement Study Medicare claims-linked database was used to identify individuals with an incident diagnosis of peripheral neuropathy using International Classification of Diseases, Ninth Revision, codes and required no previous neuropathy diagnosis during the preceding 30 months. Focusing on 15 relevant tests, we examined the number and patterns of tests and specific test utilization 6 months before and after the incident neuropathy diagnosis. Medicare expenditures were assessed during the baseline, diagnostic, and follow-up periods. RESULTS: Of the 12, 673 patients, 1031 (8.1%) received a new International Classification of Diseases, Ninth Revision, diagnosis of neuropathy and met the study inclusion criteria. Of the 15 tests considered, a median of 4 (interquartile range, 2-5) tests were performed, with more than 400 patterns of testing. Magnetic resonance imaging of the brain or spine was ordered in 23.2% of patients, whereas a glucose tolerance test was rarely obtained (1.0%). Mean Medicare expenditures were significantly higher in the diagnostic period than in the baseline period ($14,362 vs $8067, P < .001). CONCLUSIONS: Patients diagnosed as having peripheral neuropathy typically undergo many tests, but testing patterns are highly variable. Almost one-quarter of patients receiving neuropathy diagnoses undergo high-cost, low-yield magnetic resonance imaging, whereas few receive low-cost, high-yield glucose tolerance tests. Expenditures increase substantially in the diagnostic period. More research is needed to define effective and efficient strategies for the diagnostic evaluation of peripheral neuropathy.

[Knowledge of sickle cell disease and prevention methods in an urban district of Lomé, Togo]. / Connaissances de la drépanocytose et pratiques de prévention dans la population d'un district urbain de Lomé, Togo.

Despite the important frequency of the gene "S" in Togo, essential information remains insufficient to elaborate a prevention campaign on this affection. In order to assess the knowledge on sickle cell diseases as well as the prevention practices in the Togo population in one of the five districts of the township of Lomé, a cross sectional study was conducted in the third district of the township of Lomé from January 21, 2004 to January 26, 2004 in 210 natives from Togo aged of 15 and over, through a semi-structured questionnaire. The variables studied were: - the socio-demographic features and the knowledge of sickle cell disease characteristics (symptoms, biological diagnosis, treatment and means). Data collected were analysed through software Statically Package for Social Science (SPSS) version 10.0 of Windows using the chi2 test with 5% significance in the comparison of some variables. 117 women and 93 men were interviewed. Sickle cell disease was known in almost all ethnic groups but incompletely: 79.5% of the individuals knew about premarital check up but only 12.4% knew about haemoglobin electrophoresis check up. 74,8% of the people had a good knowledge of the cause of sickle cell disease, 78.6% had a fairly good knowledge of its symptoms, 57.6% knew the factors inducing attacks, 64.3% the prognosis and 69.5% the prevention methods, but a poor knowledge of the complications (62.4%), biological diagnosis (71%) and treatment (97.2%). The prevention practices were poorly adopted: 12% had an haemoglobin electrophoresis check up and 15% of them had their husband to have one as well. Professional status influenced the level of knowledge of the biological diagnosis (p=0.001) and prevention means (p=0.018). The educational level influenced biological diagnosis knowledge (p = 0.000) and prevention means (p = 0.02). On the whole, sickle disease was linked to marital status (p = 0.00). Sickle cell disease remains quite unknown in spite of the gene "S" important frequency in Togo. These results are to be taken into account to implement information, education and communication program to struggle against sickle cell disease.

The relationship between the serum free light chain assay and serum immunofixation electrophoresis, and the definition of concordant and discordant free light chain ratios.

"Stringent" complete remission in myeloma has been defined by a normal serum free light chain ratio (SFLCR) in addition to the standard criteria for CR. 2648 serial samples from 122 IgG or IgA myeloma patients were studied to explore the relationship between SFLCR and serum immunofixation electrophoresis (SIFE). SFLCR was normal in 34% of cases with positive SIFE and abnormal in 66%. SFLCR was normal in 69% of cases with negative SIFE and abnormal in 31%. When evaluated with SIFE as the benchmark, the sensitivity of SFLCR was 66% and specificity was 69%. These findings were unchanged when abnormal SFLCR values were classified as concordant (< 0.26 for lambda disease and > 1.65 for kappa) or discordant (< 0.26 for kappa disease and > 1.65 for lambda). Additional studies are required to determine the temporal relationship between SFLCR normalization and paraprotein clearance. Until then, the role of SFLCR in defining response remains controversial.

Outcomes of discretionary laboratory requesting of serum protein electrophoresis.

BACKGROUND: Discretionary laboratory requesting of serum protein electrophoresis (SPE) is widespread throughout the UK despite limited evidence to support clinical usefulness. We aimed to examine the clinical usefulness of discretionary SPE requesting on serum samples with globulins>45 g/L by documenting the number of discretionary tests performed and the number of paraproteins identified in an audit period, by determining if such findings led to further investigation/specialty referral, and by identifying the final diagnosis and subsequent management of these patients. METHODS: A retrospective one-year audit from July 2002 to June 2003 was carried out using information from biochemistry databases and review of medical records. RESULTS: Of 1332 discretionary SPEs performed in one year, 72 paraproteins were identified (5.4%). Further clinical information could be obtained in 66 cases. Appropriate follow-up occurred in 84% of cases. The most common diagnosis was monoclonal gammopathy of undetermined significance (56%). Eighteen percent of patients with an identified paraprotein were diagnosed with B-cell malignancies that warranted treatment. A further 6% progressed to requiring treatment during follow-up. CONCLUSION: Using screening criteria of serum globulins>45 g/L, one in 20 discretionary laboratory requests resulted in a clinically relevant finding. These results suggest such requesting is worthwhile and should aid future debate on the appropriateness of this practice.

Detection of kappa and lambda light chain monoclonal proteins in human serum: automated immunoassay versus immunofixation electrophoresis.

Recently, turbidimetric immunoassays for detecting and quantifying kappa and lambda free light chains (FLC) have become available and are promoted as being more sensitive than immunofixation electrophoresis (IFE) in detecting FLC monoclonal proteins. In this study, we assessed the ability of these turbidimetric assays to detect serum monoclonal proteins involving both free and heavy-chain-bound kappa and lambda light chains compared to standard immunofixation electrophoresis. Sera demonstrating a restricted band of protein migration (other than a definite M spike) by serum protein electrophoresis (SPE), which may represent early monoclonal proteins, were also examined. When compared to IFE, percent agreement, sensitivity, and specificity for the kappa-FLC and lambda-FLC were 94.6, 72.9, and 99.5% and 98.5, 91.4, and 99.7%, respectively, in detecting monoclonal proteins involving free and heavy-chain-bound light chains. The majority of sera (73.7%) demonstrating a restricted band of protein migration on SPE demonstrated abnormal IFE patterns suggestive of multiple myeloma or monoclonal gammopathy of unknown significance, but gave normal kappa/lambda FLC ratios using the turbidimetric immunoassays. In conclusion, the kappa and lambda FLC assays are significantly less sensitive (72.9 to 91.4%) than IFE, but specific in detecting serum monoclonal proteins. Moreover, the kappa/lambda ratio has little value in routine screening since the majority of sera with abnormal IFE patterns had normal kappa/lambda FLC ratios.

Linearity and detection limit in the measurement of serum M-protein with the capillary zone electrophoresis system Capillarys.

We studied the linearity and detection limits of the capillary zone electrophoresis system Capillarys in the measurement of serum monoclonal protein. Three monoclonal proteins with different isotypes and electrophoretic migrations were diluted with a hypo-gamma-globulinemic polyclonal serum pool. Mathematical linearity was observed for all monoclonal protein isotypes in the ranges studied without removing the polyclonal gamma-globulin background. Theoretical concentrations of 0.43, 0.89 and 0.33 g/L for monoclonal proteins immunoglobulin (Ig)G, IgA and IgM, respectively, gave a discernible spike by Capillarys, although they were measured as 0.76, 1.09 and 0.76g/L, respectively. We observed overestimation of monoclonal protein inversely correlated to concentrations below 15 g/L. All these limitations have to be taken into account when monitoring monoclonal proteins, because the loss of linearity and the protein background may hide an increase in concentration at low levels.

Can opportunistic case-finding of paraproteins be clinically justified?

The addition of serum protein electrophoresis by laboratory staff upon finding an increased total protein or globulin appears to be practised widely in the UK. The criteria for assessing which samples are subject to electrophoresis vary considerably. They consist of initial objective laboratory data subsequently modified, somewhat subjectively, by other laboratory data and clinical details, but have often been chosen pragmatically. The aim of the practice is to identify patients with occult B-cell malignancies that warrant treatment. While it has been lent legitimacy in many cases by involving clinical haematologists in discussions, the views of other stakeholders, including other physicians and patients, have often not been considered, thus raising a number of ethical questions that need to be addressed. The practice is reviewed against both current knowledge of B-cell malignancies and monoclonal gammopathy of undetermined significance and criteria for screening, of which this forms a particular example. The arguments for and against addition of electrophoresis are finely balanced, partly because of the very limited outcome data available. We conclude that those currently following this practice should continue to do so, there is a need to establish outcome data as widely as possible according to standard criteria and there should be involvement of physicians, patients and national bodies in discussions about the practice so that the practical and ethical issues can be addressed.

A new integrated statistical approach to the diagnostic use of two-dimensional maps.

Two-dimensional (2-D) electrophoresis is a very useful technique for the analysis of proteins in biological tissues. The complexity of the 2-D maps obtained causes many difficulties in the comparison of different samples. A new method is proposed for comparing different 2-D maps, based on five steps: (i) the digitalisation of the image; (ii) the transformation of the digitalised map in a fuzzy entity, in order to consider the variability of the 2-D electrophoretic separation; (iii) the calculation of a similarity index for each pair of maps; (iv) the analysis by multidimensional scaling of the previously obtained similarity matrix; (v) the analysis by classification or cluster analysis techniques of the resulting map co-ordinates. The method adopted was first tested on some simulated samples in order to evaluate its sensitivity to small changes in the spots position and size. The optimal setting of the method parameters was also investigated. Finally, the method was successfully applied to a series of real samples corresponding to the electrophoretic bidimensional analysis of sera from normal and nicotine-treated rats. Multidimensional scaling allowed the separation of the two classes of samples without any misclassification.

Multiwell in-gel protein digestion and microscale sample preparation for protein identification by mass spectrometry.

In-gel peptide digestion has become a widely used technique for characterizing proteins resolved by two-dimensional gel electrophoresis. Peptides generated from gel pieces are frequently contaminated with detergent and salts. Prior to matrix-assisted laser desorption/ionization-time of flight mass spectrometry analysis, these contaminants are removed using micro scale C18 sample preparation columns. In this paper, data are presented to demonstrate the application of a solvent resistant MultiScreen 96-well plate with a low peptide binding membrane and ZipTip micropipette based sample preparation. Recoveries of peptides (m/z of 1000 to 5000 Da) derived from standard protein protease digests, were estimated at various stages of the analytical process. An optimized protocol has been established and all the reagents and consumables have been packaged in a ready to use commercial kit. Data will be presented to show the application of this technology package to accelerate the throughput of protein characterization by protease fragmentation.

[An assessment of the degree of chromophore photo damage to the heme and globin components in UV-irradiated molecules and electrophoretic fractions of human carboxyhemoglobin]. / Otsenka stepeni fotopovrezhdeniia khromoforov gemovogo i globinovogo komponentov UF-obluchennykh molekul i élektroforeticheskikh fraktsii karboksigemoglobina cheloveka.

The contribution of hem and globin components of electrophoretic fractions of UV-irradiated human carboxyhemoglobin to photodestruction of the protein was studied. The changes observed are the result of summation of some processes unequal in intensity and direction that take place in microheterogeneous media of photomodified protein. Photosensitivity of hemoproteid in electrophoretic fraction depends on apoprotein condition, whereas the hem photoresistance cannot be the evidence of the photostability of the whole molecule.

Mobility of acetylated histones in sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

We describe an altered mobility for acetylated histone isoforms in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Isoforms of histones H3 and H4 with a higher acetylation degree have a slightly faster electrophoretic mobility. Since acetylation neutralizes the positive charge of the epsilon-amino group of lysine, without significantly changing the molecular mass of the protein, the acetylation-dependent mobility shift could be explained by the increase of the net negative charge of the SDS-histone complexes. A possible consequence of this differential mobility for the acetylation site determination by protein microsequencing from SDS gels is discussed.

[The use of electrophoretic methods for determining modified proteins in diabetic patients]. / Primenenie élektroforeticheskikh metodov dlia opredeleniia modifitsirovannykh belkov u bol'nykh sakharnym diabetom.

Modified proteins were determined by isoelectric focusing in borate-polyol system with subsequent colorimetry (micromethod) and electrophoresis of blood serum on paper with subsequent TCA-ethanol treatment. Increased levels of glycated hemoglobin and modified albumin and changed light absorbance of glycated albumin were detected. The levels of glycated hemoglobin assessed by the micromethod and colorimetry without calibration did not correlate.

[The dynamics of the alpha 1-protease inhibitor and alpha 2-macroglobulin in very-low-birth-weight newborns]. / Dinamika na alfa 1-inkhibitor na proteazata i alfa 2-makroglobulin pri novorodeni s mnogo nisko teglo.

OBJECTIVES: The purpose is to improve the neonatal outcome and to prognosticate the risk for developing respiratory problems. For that reason the serum concentrations of 1-inhibitor of proteolysis (alpha 1-IP) and 2-macroglobuline (alpha 2-M) at very low birth weight infants (< 1500 g) were investigated. STUDY DESIGN: The research is prospective and it is made for the period from January 1st 1995 up to December 31st 1995.17 very low birth weight infants (VLBWI) were the main group and 19 full term babies were the control group. The method of so called 'rocket' immunoelectrophoresis was used (this method was an innovation of D. Nankova [correction of P. Nancova], V. Kamenova, 1990). Blood was taken from babies just after delivery and at 3rd-4th day. Alternative, variantative and graphic analyses were used. RESULTS: The average value of alpha 1-IP for VLBWI was 2.036 g/l (SD +/- 0.44 g/l) for the 1st test and 2.31 g/l (SD +/- 0.41 g/l) for the 2nd test. The average value of the healthy full term babies was 2.055 g/l (SD +/- 0.37 g/l) for both tests. The lowest values of alpha 1-IP (from 0.6 g/l to 1.9 g/l) were in babies with genetic and respiratory problems. The main group had an average value of alpha 2-M 3.44 g/l (SD +/- 0.92 g/l) for the 1st test and a little higher values for the 2nd test -4.99 g/l (SD +/- 0.72 g/l) with significant differences p(t) < 0.0001. The lower levels of alpha 2-M were founded in VLBWI and they were significant for decreased protective reactions against pathologic micro-organisms. CONCLUSIONS: Control of serum concentrations of alpha 1-IP and alpha 2-M are an additional diagnostic and prognostic criterion in VLBWI for developing respiratory problems.

[The distribution of haptoglobin phenotypes among the population of Ukraine]. / Raspredelenie fenotipov gaptoglobina sredi naseleniia Ukrainy.

The results of investigation of haptoglobin (Hp) types in 596 donor blood samples in some towns of Ukraine (Dnepropetrovsk, Kharkov, Odessa, Kiev, Uzhgorod, Zhitomir) are presented. Three normal Hp types (Hp1-1, Hp2-1 and Hp2-2) have been found. The reliable interpopulation differences in the Hp types frequency were not found. On the whole the Hp types frequency in the type Hp1-1 comprised 12.7%. In the type Hp2-1-48.1% and in the type Hp2-2-36.5%. The frequency of the gene Hp1 is 0.38. The frequency of the Hp types and of the gene Hpl in Ukraine is similar to that in population of Eastern Europe and European Part of Russia.

Evaluation of a new automated system for the determination of CK-MB isoforms.

We evaluated a new analyzer (Cardio REP) specifically designed for cardiac CK-MB isoenzyme and isoforms activity, with a performance time of 24 minutes. Ten AMI patients, with times elapsed between the onset of chest pain and admission to hospital ranging from 30 minutes to 4 hours, were monitored every 3-4 hours until the 16th hour of hospitalization. In each serum sample, in addition to total CK-MB and CK-MB isoforms measured by the Cardio REP analyzer, we also assayed total CK activity, CK-MB activity by immunoinhibition method, CK-MB mass concentration, CK-MB isoforms by REP method, troponin T, and myoglobin. The precision study demonstrated acceptable within assay and between assay CVs% for total CK-MB (8.1 and 10.4), MB1 (9.1 and 14.2), and MB2 (9.1 and 8.2) isoforms. The method was found to be linear up to 371 U/L for MB2 isoform fraction and up to 516 U/L for total CK-MB. Results for CK-MB obtained with the Cardio REP correlated well with those for CK-MB activity obtained with the immunoinhibition method (r = 0.869) and those of CK-MB mass concentration (r = 0.923). The sensitivity of the Cardio REP CK isoforms method was found to be greater than that of the REP CK isoforms method. Time to first increased value of MB2/MB1 ratio and MB2 isoform was earlier in comparison to that for CK-MB mass concentration and similar to that for myoglobin, a marker that, however, lacks specificity. The diagnostic efficiency of CK-MB isoforms and the availability of a real-time, fully automated method for their measurement suggest that utilization of this biochemical marker in emergency for the early diagnosis of AMI.