Prevention of medical errors is a major goal of healthcare, though healthcare workers themselves have not yet fully accepted or implemented reliable models of system error, and neither has the public. While there is widespread perception that most medical errors arise from an inappropriate or delayed clinical management, the issue of laboratory errors is receiving a great deal of attention due to their impact on the quality and efficiency of laboratory performances and patient safety. Haemolytic specimens are a frequent occurrence in clinical laboratories, and prevalence can be as high as 3.3% of all of the routine samples, accounting for up to 40%-70% of all unsuitable specimens identified, nearly five times higher than other causes, such as insufficient, incorrect and clotted samples. This article focuses on this challenging issue, providing an overview on prevalence and leading causes of in vivo and in vitro haemolysis, and tentative guidelines on identification and management of haemolytic samples in clinical laboratories. This strategy includes continuous education of healthcare personnel, systematic detection/quantification of haemolysis in any sample, immediate clinicians warning on the probability of in vivo haemolysis, registration of non-conformity, completing of tests unaffected by haemolysis and request of a second specimen for those potentially affected.
Advanced statistical analysis of a panel of six selected plasma biomarkers on samples obtained during the secretory phase or during menstruation allows the diagnosis of both minimal-mild and moderate-severe endometriosis with high sensitivity and clinically acceptable specificity.
Laboratory diagnostics, a pivotal part of clinical decision making, is no safer than other areas of healthcare, with most errors occurring in the manually intensive preanalytical process. Patient misidentification errors are potentially associated with the worst clinical outcome due to the potential for misdiagnosis and inappropriate therapy. While it is misleadingly assumed that identification errors occur at a low frequency in clinical laboratories, misidentification of general laboratory specimens is around 1% and can produce serious harm to patients, when not promptly detected. This article focuses on this challenging issue, providing an overview on the prevalence and leading causes of identification errors, analyzing the potential adverse consequences, and providing tentative guidelines for detection and prevention based on direct-positive identification, the use of information technology for data entry, automated systems for patient identification and specimen labeling, two or more identifiers during sample collection and delta check technology to identify significant variance of results from historical values. Once misidentification is detected, rejection and recollection is the most suitable approach to manage the specimen.
Background: In vitro hemolysis, the prevailing cause of preanalytical error in routine laboratory diagnostics, might influence the reliability of several tests, affect the quality of the total testing process and jeopardize patient safety. Although laboratory instrumentation is now routinely equipped with systems capable of automatically testing and eventually correcting for hemolysis interference, to our knowledge there are no reports that have compared the efficiency of different analytical platforms for identifying and classifying specimens with hemolysis. Methods: Serum from a healthy volunteer was spiked with varying amounts of hemolyzed blood from the same volunteer, providing a serum free hemoglobin concentration ranging from 0.0 g/L to 2.0 g/L as measured by the reference cyanmethemoglobin assay. The spiked serum samples were shipped to seven sepa-
Procedures for the synthesis, separation and determination of structure of the bilirubin-IX isomers are described. 1. The four biliverdin-IX isomers were prepared by oxidative cleavage of haemin and were separated as their dimethyl esters. The individual esters were reduced with NaBH4, and the bilirubin esters obtained were subjected to alkaline hydrolysis yielding the corresponding bilirubin-IX isomers. 2. The bilirubin-IX isomers were structurally characterized (a) at the tetrapyrrolic stage by mass spectrometry of their trimethylsilyl derivatives and (b) by formation and structural analysis of their dipyrrolic ethyl anthranilate azo derivatives. 3. The absorption spectrum of bilirubin-IX alpha differed strikingly from the spectra of the other isomers. The presence of a pronounced shoulder around 453 nm in the spectrum of bilirubin-IXbeta allows easy differentiation from bilirubin-IXdelta. Methylation of the carboxyl groups largely eliminates the spectral differences between the IXalpha- and non-alpha isomers. 4. The bilirubin-IX isomers are conveniently separated by t.l.c. Detection and unequivocal identification is possible on a micro-scale by (a) t.l.c. with respect to reference compounds and (b) subsequent formation and t.l.c. of the more stable ethyl anthranilate azopigments. 5. Pronounced differences in polarity, i.e. solvent distribution, between the bilirubin-IX isomers indicate that a re-evaluation of conclusions reached previously with regard to the presence in, or absence from, biological fluids of some isomers and their relative amounts is needed.
1. In aqueous solution above pH7 bilirubin-IXalpha 1-O-acylglucuronide rapidly isomerizes to the non-C-1 glucuronides by sequential migration of the bilirubin acyl group from position 1 to positions 2, 3 and 4 of the sugar moiety. The transformations are enhanced by increasing the pH. Compared with the rates at 37 degrees C the transformations are rather slow at 0 degrees C. Virtually complete inhibition is observed at values below pH6. The isomerization at 25 degrees C and pH 7.4 is not affected by the presence in the solutions of a molar excess of human serum albumin. 2. Isomerization in bile kept at 37 degrees C at pH7.7-7.8 is probably non-enzymic, as the rates of change are similar to those observed under comparable conditions for aqueous solutions of glucuronides of bilirubin-1Xalpha and of azodipyrrole. 3. Analysis without delay of normal biles of man and rats collected at 0 degrees C over a maximum period of 10 min shows that the bilirubin-IXalpha mono- and di-glucuronides consist exclusively of the 1-O-acyl isomers. 4. The mixtures of the four positional isomers of bilirubin-IXalpha glucuronide found in freshly collected biles of man and rats with cholestasis probably originate from initially synthesized 1-O-acylglucuronide by the same mechanism of sequential migration as has been observed in aqueous solutions of conjugated bilirubin-IXalpha.
Capillary zone electrophoresis (CZE) of serum proteins is increasingly gaining impact in clinical laboratories. In this report, we evaluate automated capillary zone electrophoresis by Capillarys (Sebia, France). Within-run and between-run imprecision for the five electrophoretic fractions was <2% and <6%, respectively. Data obtained with Capillarys correlated with results obtained with agarose gel electrophoresis and Paragon CZE 2000 (Beckman Coulter, USA). Analysis of serum obtained from patients with inflammation, nephrotic syndrome, bisalbuminemia, and alpha1-antitrypsin deficiency revealed that Capillarys was able to detect these abnormalities. Two hundred thirty eight samples were analyzed by agarose gel electrophoresis, Capillarys, capillary electrophoresis using Paragon CZE 2000 system, and immunofixation. Sample selection was based on the presence of a disturbed morphology (e.g., spike) of the protein profile or hypogammaglobulinemia on agarose gel electrophoresis and/or Capillarys. Immunofixation revealed the presence of a monoclonal protein, oligoclonal bands, polyclonal pattern, and a normal profile in, respectively, 89, 66, 19, and 64 samples. With Capillarys, Paragon, and agarose gel electrophoresis, a spike and/or disturbed morphology of the profile was found in 222, 182, and 180 samples, respectively. In these samples, immunofixation was negative in 73 (33%), 46 (25%), and 39 (22%) samples, respectively. These data indicate that Capillarys has a lower specificity than agarose gel electrophoresis and Paragon 2000. Of the 89 samples with a monoclonal protein, Capillarys, Paragon, and agarose gel electrophoresis failed to detect, respectively, three, three, and one monoclonal protein(s). Interferences by radio-opaque agents, complement degradation products, fibrinogen, and triglycerides are described. In conclusion, automated capillary zone electrophoresis with Capillarys provides for reproducible, rapid, and reliable serum electrophoresis.
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