A Two-Genome Portrayal of Mitochondrial Disorders: A Review with Clinical Presentations.

Disorders of mitochondrial function are responsible for many inherited neuromuscular and metabolic diseases. Their combination of high mortality, multi-systemic involvement, and economic burden cause devastating effects on patients and their families. Molecular diagnostic tools are becoming increasingly important in providing earlier diagnoses and guiding more precise therapeutic treatments for patients suffering from mitochondrial disorders. This review addresses fundamental molecular concepts relating to the pathogenesis of mitochondrial dysfunction and disorders. A series of short cases highlights the various clinical presentations, inheritance patterns, and pathogenic mutations in nuclear and mitochondrial genes that cause mitochondrial diseases. Graphical and tabular representations of the results are presented to guide the understanding of the important concepts related to mitochondrial molecular genetics and pathology. Emerging technology is incorporating preimplantation genetic testing for mtDNA disorders, while mitochondrial replacement shows promise in significantly decreasing the transfer of diseased mitochondrial DNA (mtDNA) to embryos. Medical professionals must maintain an in-depth understanding of the gene mutations and molecular mechanisms underlying mitochondrial disorders. Continued diagnostic advances and comprehensive management of patients with mitochondrial disorders are essential to achieve robust clinical impacts from comprehensive genomic testing. This is especially true when supported by non-genetic tests such as biochemical analysis, histochemical stains, and imaging studies. Such a multi-pronged investigation should improve the management of mitochondrial disorders by providing accurate and timely diagnoses to reduce disease burden and improve the lives of patients and their families.

The Novel Use of Umbilical Cord Blood to Obtain Complete Blood Counts for Critical Neonatal Assessment.

BACKGROUND: Neonates undergoing clinical evaluations are often subjected to potentially painful phlebotomy for laboratory tests. The use of cord blood laboratory values for admission has been suggested as a means to decrease the risk of painful venipuncture and anemia. METHODS: Peripheral and umbilical cord blood complete blood count (CBC) results were obtained from infants who required a CBC. Results were compared using the Sysmex XN heme analyzer (Sysmex, Kobe, Japan). RESULTS:  White blood cell (WBC) and hemoglobin (HgB) values were significantly higher in peripheral samples than in cord samples. The mean cord WBC count was 14.1 × 103/mm3 versus 15.6 × 103/mm3 peripherally (p < 0.001). The mean cord HgB was 15.8 g/dL versus 16.8 g/dL peripherally (p < 0.001). Cord platelet (Plt) counts were, conversely, lower in peripheral samples than in cord samples (264.8 × 103/mm3 versus 242.3 × 103/mm3, respectively; p < 0.001). Although statistically different, the mean CBC values from both samples were within the reference ranges. Delayed cord clamping (DCC) increased peripheral versus cord HgB difference nearly threefold (0.6-1.7 g/dL; p = 0.01). CONCLUSIONS: Cord blood is an acceptable source for CBC blood sampling in newborn infants and can be used for clinical decisions. CBC laboratory values for cord blood remained within the peripheral blood reference range, with slight variability between the two samples.

Massive Transfusion Protocol in a 69 Year Old Woman with Alloantibodies.

Unlike routine blood transfusions that are managed by attending providers and rely on compatibility testing, massive transfusions are managed by the trauma team members, who usually do not have immediate access to compatibility testing. Incompatible C or E antigens, when present in uncrossmatched O positive blood, require transfusion support so that health care professionals can manage potential causes for extravascular hemolysis. Herein, we describe a massive transfusion situation in which immediate patient management was required to mitigate potentially fatal clinical consequences of transfused red blood cell antibodies. In addition, this case study shows how the utility of chemistry and hematology laboratory results can illustrate the complexities of massive transfusion management in the context of incompatible C or E antigens.

Effects of lubricants and wash solutions on semen evaluation in a fertility clinic laboratory.

OBJECTIVE: The complex nature of semen components and the various collection procedures make standardization of semen analysis (SA) challenging. Therefore, the main goal of this study was to optimize and improve the quality and utility of the SA report. METHODS: Semen samples (n = 20) were split into 2 aliquots to compare 2 isolation gradients. Samples incubated in the different wash medium were evaluated for motility, forward progression, morphology, and suitability for intrauterine insemination (IUI). Another group (n = 20) was evaluated for IUI utility without and with a lubricant to compare motility and sperm count. RESULTS: There were no significant differences in motility, forward progression, or morphology with or without a lubricant. With respect to gradient types, PureSperm 40/80 isolated significantly higher yields of motile sperm than the isolate. In comparing wash media, at 2 hours PureSperm was significantly higher in both motility and count compared to Irvine culture media. CONCLUSION: This study represents a significant advance toward improved applications and methods for SA testing. Continued standardization and improvements in SA will require additional evaluation of lab testing methods.

How can a methadone and an opiate-positive immunoassay result be reconciled in a patient prescribed only OxyContin and Wellbutrin?

Appropriate management of patients in pain clinics can be complex and sometimes confusing because providers must correctly interpret multiple sources of patient information. The correct interpretation of laboratory results is essential to guide subsequent patient treatment and management; however, laboratory and clinical pictures can appear to be conflicting in cases of substance abuse. Incorrect interpretation of laboratory results can multiply negative impacts on clinical outcomes and may lead to patient harm or death. This report introduces the complex nature involved in understanding and interpreting urine drug testing (UDT) results in pain patients who are prescribed opioid medications. Laboratory testing examples of UDT results are provided to illustrate the sometimes discordant nature of UDT interpretation. This case study describes one method of approaching cases where laboratory result interpretation in pain clinic patients is essential for medical treatment and management. The case presented in this manuscript illustrates a reconciliation of an opiate positive immunoassay result in a patient who was prescribed only OxyContin and Wellbutrin after traumatic amputations.

Are renal reference intervals required when screening for plasma cell disorders with serum free light chains and serum protein electrophoresis?

Renal impairment and polyclonal hypergammaglobulinemia may abnormally increase the serum free light chain (sFLC) ratio, giving false-positive results with current reference intervals. We measured sFLCs with concomitant serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP) in 281 patients. Results were interpreted relative to renal function (serum creatinine concentrations) and polyclonal hypergammaglobulinemia. Overall, 78 plasma cell disorders (PCDs) were detected with the serum panel of SPEP/sFLC vs 76 with SPEP/UPEP. In 13 samples with negative SPEP/UPEP, mildly increased ratios up to 3.1 (normal, 0.26-1.65) were observed: 10 were associated with increased serum creatinine and 1 with polyclonal hypergammaglobulinemia; 2 were unassociated with either condition. In 2 samples, decreased kappa/lambda ratios were identified that were clinically significant despite normal SPEP/UPEP. Two monoclonal gammopathies were identified with UPEP and sFLC, but samples were normal with SPEP. Screening for PCDs with a serum panel consisting of SPEP and the sFLC assays is a highly sensitive approach that could eliminate the need for UPEP. A mildly increased kappa/lambda ratio up to 3.1 was observed with increased serum creatinine and/or polyclonal hypergammaglobulinemia that was consistent with pathophysiologic changes, and, therefore, renal reference intervals are recommended.

Performance of the Roche second generation hemoglobin A1c immunoassay in the presence of HB-S or HB-C traits.

Blood HbA1c determination is a powerful tool for the evaluation and management of patients with diabetes mellitus. Many HbA1c analytical methods demonstrate bias in samples from patients with hemoglobinopathies. This study evaluated the analytical performance of Roche Diagnostics' 1st and 2nd generation HbA1c assays in patients with or without hemoglobinopathies whose HbA1c levels were elevated or normal, respectively. Boronate-affinity high performance liquid chromatography (HPLC) served as the reference method. Whole blood samples were collected from 80 patients with HbS or HbC whose group mean HbA1c value was elevated and also from 80 patients without hemoglobinopathy whose HbA1c values were in the well-controlled range. Each sample was assayed for HbA1c by the Primus boronate-affinity HPLC technique and by Roche's 1st and 2nd generation immunoassays using a Cobas Integra 800 analytical system. Results by the HPLC technique were compared with the results of both Roche assays by linear regression and Bland-Altman analysis. The 1st and 2nd generation assays yielded regression lines and correlation values vs HPLC assay of y = 1.43x - 1.59; R(2) = 0.83, and y = 0.94x + 0.10; R(2) = 0.92, respectively, in the 80 patients with hemoglobinopathies. The mean difference and the +/-2SD range were greater in the 1st than in the 2nd generation assay (2.68, +/-2.07 vs -0.54, +/-0.86, respectively). The 2nd generation assay also showed better performance than the 1st generation assay in samples from the 80 patients without hemoglobinopathy. In conclusion, this study validates the accuracy of Roche's 2nd generation assay, which is substantially improved over Roche's 1st generation HbA1c assay.

To what extent are free testosterone (FT) values reproducible between the two Washingtons, and can calculated FT be used in lieu of expensive direct measurements?

Free testosterone (FT) measurement by equilibrium dialysis and liquid chromatography-tandem mass spectroscopy (LCMS/MS) is the "gold standard." We hypothesized that calculated FT values could substitute for measured values; compared FT results reported by Walter Reed Army Medical Center (WRAMC), Washington, DC, with results reported by the Seattle Veterans Affairs Health Care System, Seattle, WA, for 3 patient groups; and evaluated the calculated FT values by gold-standard measurements. Groups 1 and 2 included samples from 54 patients evaluated in Seattle and 94 evaluated at a primary care clinic in Alaska whose samples were analyzed in Seattle, respectively, whose care resulted in ordering an FT measurement. Group 3 included samples from 64 patients evaluated in endocrine WRAMC clinics. Calculated FT values between the 2 facilities demonstrated a strong correlation (R2 = 0.98) for all 212 patients. In a comparison of calculated FT values with measured levels, group 3 had an R2 = 0.93; however, samples with FT values less than 50 pg/mL had a poorer correlation (R2 = 0.45). Calculated FT values may accurately reflect and be substituted in the clinical setting for gold-standard values when levels are more than 50 pg/mL.

Assessment of serum free light chain assays for plasma cell disorder screening in a Veterans Affairs population.

This study evaluated serum kappa and lambda free light chain (FLC) concentrations in a Veterans Affairs (VA) population. We hypothesized that our older, mostly male, population should not differ in serum FLC ranges from levels previously established for younger male and female populations and that the assay would improve our screening protocol for plasma cell dyscrasias (PCD). Serum kappa and lambdaFLC were assayed in 312 consecutive serum samples collected during a 16-week period from veterans whose clinical presentation indicated a need for serum protein electrophoresis (SPEP) analysis. We reviewed our laboratory information system (LIS) files to evaluate the patients' diagnoses and treatment status in conjunction with serum FLC levels. All assays and validation studies were conducted using an immunoturbidimetric method with a Roche/Hitachi 911 modular analytical system. The intra-assay variability (CV) was <5%, based on 13 replicate assays of 4 control samples and 1 blank sample. Of the 312 patients, the SPEP results were normal in 235 and abnormal in 77. Of the 235 patients with normal SPEP results, 37 had abnormal FLC values and 20 of these were diagnosed as PCD. Of the 77 patients with abnormal SPEP results, only 9 had diagnoses unrelated to PCD. Using the FLC assay in conjunction with retrospective reviews of medical records, we obtained an 86% detection rate of PCD. This detection rate increased to 100% when both SPEP and FLC results were considered. In conclusion, this study documents an important role for serum FLC assays in diagnosing and monitoring PCD in a VA population. Our results support previously established serum FLC reference ranges that were obtained in younger, male and female populations. Using the serum FLC results in conjunction with SPEP results improves the sensitivity and specificity for managing VA patients whose clinical presentation indicates the need to evaluate PCD.

Can an immunoassay become a standard technique in detecting oxycodone and its metabolites?

Opiate toxicology testing is routinely performed in the hospital setting to identify abusers and/or to determine those patients who are not taking prescribed opiate analgesics such as oxycodone. Commercially available assays for opiate detection in urine have decreased sensitivity for oxycodone, which contributes to a high false-negative rate. Functioning as a beta site, our Veterans Affairs hospital evaluated a new enzyme immunoassay, DRI Oxycodone Assay, for its use in the qualitative and semiquantitative detection of oxycodone in urine. We hypothesize that an immunoassay for oxycodone with superior sensitivity and specificity, when compared to the traditional opiate assays, would reduce the need for more expensive and time-consuming confirmatory testing. We used the new liquid homogenous enzyme immunoassay to determine oxycodone results in a total of 148 urine samples from 4 different sample groups. Gas chromatography-mass spectroscopy was subsequently used to confirm the presence or absence of oxycodone (or its primary metabolite, noroxycodone). We also evaluated within-run, between-run, and linearity studies and conducted a crossover study to establish a cutoff value for oxycodone. In our patient population, we used the new DRI immunoassay to evaluate 17,069 urine samples to estimate oxycodone misuse profiles (patients not taking prescribed oxycodone or taking oxycodone without a prescription) during a 4-month period. The sensitivity and specificity of the new oxycodone immunoassay were 97.7% and 100%, respectively, at the cutoff concentration of 300 ng/mL. The assay linearity was 1,250 ng/mL, and the sensitivity was 10 ng/mL. Within-run precision and between-run coefficient of variation were 2.3% and 1.8%, respectively. None of the 15 compounds that we evaluated for interference had crossover significant enough to produce a positive oxycodone result when using 300 ng/mL as the cutoff value. None of the 17,069 oxycodone immunoassays was followed with a request for confirmation. Among patients with positive results (n = 224), 93 (41.5%) were not prescribed oxycodone. The new DRI Oxycodone Assay is a sensitive and specific screening test for the determination of oxycodone. The improved opiate screening results may lead to better patient and prescription management, to decreased laboratory spending, and to the identification of oxycodone abusers, which could result in decreased oxycodone-related mortality.

Albumin cobalt binding assay to rule out acute coronary syndrome.

The purpose of this study was to validate the Albumin Cobalt Binding (ACB) assay at the Seattle Veterans Affairs (VA) Hospital to determine if it would provide an earlier rule-out of acute coronary syndrome (ACS) in patients, compared to current use of cardiac injury markers. This study compares the distribution of ischemia modified albumin (IMA) values of our patient population to those provided by the kit manufacturer. IMA values were determined photometrically on a Roche Modular Analytical System on 200 subjects: 69 subjects not experiencing chest pain (normals), 78 subjects presenting to the emergency room (ER) with chest pain whose initial and subsequent troponin results were negative (non-converters), and 53 subjects presenting to the ER with chest pain whose initial troponin result was negative but subsequent troponin results were positive (converters). Based on the relationships between IMA values in the initial samples from the non-converters and converters, we constructed a ROC curve to identify an optimum IMA rule-out value. The IMA values (mean+/-SD) for the normals, non-converters, and converters were 89+/-7.1, 100+/-13.9, and 126+/-14.1 U/ml, respectively, and each mean was statistically different from the means of the other groups. The ROC curve comparing converters and non-converters showed an area of 0.89 (p <0.001) compared to the line of identity. An IMA cut-off of 97 U/ml gives a 98% sensitivity and 45% specificity and may be the best decision point to differentiate between these groups in our population. Nine of 78 non-converters were classified as having unstable angina. In conclusion, the ACB assay has a strong negative predictive value and sensitivity in our population for predicting the troponin results at 6 to 24 hr post-presentation. Because ACB results may be facility- and instrument-dependent, each facility should conduct an independent ROC analysis to determine the optimal IMA rule-out level. The ACB assay, when used in conjunction with cardiac injury markers and assessment of unstable angina, holds promise in reducing inappropriate low-risk hospital admissions and improving the clinical management of patients with chest pain.

Cardiac injury markers and a failed algorithm: can accurate assessment of acute myocardial infarction be cost effective?

CONTEXT: Most studies assessing the use of cardiac injury markers, such as cardiac troponin I (cTnI), total creatine kinase (CK Total), and the cardiac isoenzyme of CK (CK-MB), agree that cTnI is the most specific test for diagnosing acute myocardial infarction (AMI). However, throughout the literature, there are ambiguities and contradictions on assay-ordering criteria. Inconsistent ways of viewing biochemical assessment of acute chest pain leads to cardiac injury marker assay-ordering patterns that can be nonspecific, ambiguous, and costly. OBJECTIVE: This study set out to design a cost-effective strategy and to outline criteria for ordering cardiac injury marker assays. This is accomplished by comparing Madigan Army Medical Center (MAMC) testing patterns to guidelines described in recently published prospective hospital studies investigating the markers. DESIGN: This was a retrospective study analyzing the patterns of 34,412 cardiac marker assays performed on 4,861 patients during 1999 and 2000 at MAMC. A total of 5,850 assays were run from 1,223 patients during the first 6 months of 2001. RESULTS: The MAMC chemistry section spent more than $100,000 during 1999 for the measurement of cardiac injury markers. During 2000, an algorithm was implemented to place controls on ordering; however, the same dollar amount was spent. CK Total, CK-MB, and cTnI testing represent 3.5% of the tests performed in the chemistry section, but they consumed about 20% of the supply budget. This disproportionate expenditure is attributable to numerous, dissimilar, and voluminous ordering patterns. CONCLUSIONS: Proper use of cardiac marker assays can lead to rapid and accurate diagnosis of AMI and subsequently save lives. This study demonstrates that cTnI is the only marker needed for accurate and more cost-effective assessment of AMI.