Entries Tagged as 'Arch Pathol Lab Med'
Drug-induced thrombocytopenia.
Arch Pathol Lab Med. 2009 Feb;133(2):309-14
Authors: Kenney B, Stack G
Drug-induced thrombocytopenia was first described in the 19th century, yet our understanding of its pathogenesis continues to evolve. The list of drugs implicated in drug-induced thrombocytopenia is extensive and growing. Many, if not most, of these medications induce thrombocytopenia by immune mechanisms. Because the degree of thrombocytopenia can put patients at risk for serious bleeding, a prompt diagnosis is key to clinical management. The laboratory approach to diagnosing drug-induced thrombocytopenia is 2-pronged. First, nondrug causes of thrombocytopenia must be ruled out. Second, testing for drug-dependent platelet antibodies, available at specialized reference laboratories, often can identify the offending medication, although usually not in time for initial clinical management. Once a medication is suspected of causing thrombocytopenia, it must be discontinued promptly, and the patient should be monitored closely. Thrombocytopenia generally resolves quickly after offending medication withdrawal, and the prognosis of drug-induced thrombocytopenia is then excellent.
PMID: 19195976 [PubMed - indexed for MEDLINE]
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Notification of critical results: a College of American Pathologists Q-Probes study of 121 institutions.
Arch Pathol Lab Med. 2008 Dec;132(12):1862-7
Authors: Valenstein PN, Wagar EA, Stankovic AK, Walsh MK, Schneider F
CONTEXT: Hospital accreditors are placing increased emphasis on the timeliness with which critical laboratory results are reported to caregivers. OBJECTIVE: To measure the speed of critical result notification at a group of laboratories, identify factors associated with faster reporting, and place findings in the context of the time required to transport and test specimens and to correct critical abnormalities. DESIGN: Contemporaneous review of 3545 inpatient and emergency department critical result notifications in 121 laboratories enrolled in the College of American Pathologists Q-Probes program. RESULTS: The median laboratory required a median of 5 minutes for staff to notify someone about a critical result once testing was complete. Laboratories affiliated with smaller institutions (P = .01), rural laboratories (P = .001), and sites that called results before releasing them from the laboratory computer (P = .02) were able to notify caregivers more quickly. There was variation among institutions in the time it took to notify caregivers (interquartile range, 1.5-8 minutes). At the median facility, notification took place 56.5 minutes after the specimen had been collected. CONCLUSIONS: The time required to notify caregivers of a critical laboratory result is a small proportion of the time taken to collect and test specimens or the time that has been reported for caregivers to correct abnormalities. Although failure to notify caregivers of critical results may represent an important patient safety vulnerability, the timeliness of laboratory notification is a minor contributor to total test turnaround time at most institutions.
PMID: 19061281 [PubMed - indexed for MEDLINE]
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Reduction of blood loss from laboratory testing in hospitalized adult patients using small-volume (pediatric) tubes.
Arch Pathol Lab Med. 2008 Dec;132(12):1916-9
Authors: Sanchez-Giron F, Alvarez-Mora F
CONTEXT: Blood loss from laboratory testing (BLLT) can be significant in hospitalized patients. It is a common practice to draw full large-volume tubes of blood from adults. OBJECTIVE: To determine whether BLLT occurred when a small-volume (pediatric) blood collection tube (SVT) was substituted for each large-volume blood collection tube and to note whether an adequate sample still was obtained. DESIGN: During 2 consecutive weeks, hospital test requisitions were reviewed to collect patient demographics, tests requested, and number and type of tubes obtained. The amount of blood collected and BLLT per patient were calculated. Reduced sample requirements were calculated, and phlebotomists and ward nurses were required to use SVTs. After 2 weeks of familiarization, data were collected as previously described. Laboratory technicians logged problems related to the use of SVTs. RESULTS: Baseline: 227 patients had 664 requisitions, and median BLLT per patient was 13.5 mL (interquartile range [IQR], 7.6-27.3 mL). In critical care patients, the median was 19.9 mL (IQR, 12.0-35.8 mL), and maximum BLLT was 159.8 mL. Intervention phase: 246 patients had 696 requisitions, median BLLT was 3.7 mL (IQR, 1.2-6.3 mL; P < .001). In critical care patients, the median was 5.1 mL (IQR, 2.3-10.9 mL), and maximum BLLT was 61.8 mL (P < .001). All tests requested could be performed using SVTs, and no additional blood collections were required. Use of SVTs reduced overall BLLT per patient by 73% and by 74% in critical care patients. CONCLUSIONS: By decreasing the size of the blood collection tube for adults, we were able to markedly reduce BLLT without noting any insufficient specimen volumes.
PMID: 19061290 [PubMed - indexed for MEDLINE]
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Primary central nervous system lymphoma.
Arch Pathol Lab Med. 2008 Nov;132(11):1830-4
Authors: Bhagavathi S, Wilson JD
Primary central nervous system lymphoma (PCNSL) is an uncommon extranodal non-Hodgkin lymphoma. Its incidence has increased during the last 3 decades and has been reported in both immunocompromised and immunocompetent patients. Immunocompromised patients are affected at a younger age compared with immunocompetent patients. It presents with raised intracranial pressure and focal neurologic and neuropsychiatric symptoms. The lesions are typically solitary. The majority of the lesions are located in the periventricular area, whereas in a few cases they are located in the supratentorial area. Diffuse large B-cell lymphomas constitute most PCNSLs, whereas T-cell, low-grade, anaplastic, and Hodgkin lymphomas are rarely encountered. The morphology of PCNSL shows a characteristic angiocentric pattern and is positive for B-cell markers by immunohistochemistry. The differential diagnosis of PCNSL includes central nervous system gliomas, metastatic tumors, demyelinating disorders, subacute infarcts, and space-occupying lesions due to an infectious etiology. The understanding of the molecular mechanisms involved in the pathogenesis of PCNSL and the identification of molecular biomarkers have lagged behind that of systemic nodal lymphomas. Primary central nervous system lymphomas are treated with combined radiotherapies and chemotherapies. The prognosis for PCNSL is worse than for other extranodal lymphomas.
PMID: 18976024 [PubMed - indexed for MEDLINE]
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“Give us this day our daily bread”–evolving concepts in celiac sprue.
Arch Pathol Lab Med. 2008 Oct;132(10):1594-9
Authors: Upton MP
CONTEXT: Celiac sprue affects genetically susceptible individuals, who develop small intestinal injury and malabsorption following dietary exposure to gluten. The histologic features are nonspecific but characteristic. OBJECTIVES: To outline the histologic features of celiac sprue and the necessary clinical context to permit a diagnosis of celiac sprue, to assist the pathologist to identify artifactual biopsy changes that may mimic sprue, to define the differential diagnosis for conditions with a similar histology, and to review historic investigations of this disease. DATA SOURCES: Sources include the historic experiments and clinical work of members of the Gastroenterology Division of the Department of Medicine and experiences with gastrointestinal pathology consultation material at the University of Washington, Seattle, with reference to selected peer-reviewed articles. CONCLUSIONS: Confirmation of a diagnosis of celiac sprue is 2-fold: first, biopsy evidence of a characteristic, but nonspecific, pattern of injury including villous blunting or flattening, surface enterocyte damage, and increased intraepithelial lymphocytes; and second, dramatic clinical response to a gluten-free diet. Complete gluten removal from the diet is effective treatment for patients with symptoms of malabsorption; however, lifelong adherence to the diet is expensive, socially limiting, and nearly impossible on a contemporary diet with manufactured foodstuffs. Therefore, pathologists should avoid overdiagnosis of celiac disease based on minimal, nonspecific histologic changes.
PMID: 18834217 [PubMed - indexed for MEDLINE]
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Specimen labeling errors: a Q-probes analysis of 147 clinical laboratories.
Arch Pathol Lab Med. 2008 Oct;132(10):1617-22
Authors: Wagar EA, Stankovic AK, Raab S, Nakhleh RE, Walsh MK
CONTEXT: Accurate specimen identification is critical for quality patient care. Improperly identified specimens can result in delayed diagnosis, additional laboratory testing, treatment of the wrong patient for the wrong disease, and severe transfusion reactions. Specimen identification errors have been reported to occur at rates of 0.1% to 5%. OBJECTIVE: To determine the frequency of labeling errors in a multi-institutional survey. DESIGN: Labeling errors were categorized as: (1) mislabeled, (2) unlabeled, (3) partially labeled, (4) incompletely labeled, and (5) illegible label. Blood specimens for routine or stat chemistry, hematology, and coagulation testing were included. Labeling error rates were calculated for each participant and tested for associations with institutional demographic and practice variable information. RESULTS: More than 3.3 million specimen labels were reviewed by 147 laboratories. Labeling errors were identified at a rate of 0.92 per 1000 labels. Two variables were statistically associated with lower labeling error rates: (1) laboratories with current, ongoing quality monitors for specimen identification (P = .008) and (2) institutions with 24/7 phlebotomy services for inpatients (P = .02). Most institutions had written policies for specimen labeling at the bedside or in outpatient phlebotomy areas (96% and 98%, respectively). Allowance of relabeling of blood specimens by primary collecting personnel was reported by 42% of institutions. CONCLUSIONS: Laboratories actively engaged in ongoing specimen labeling quality monitors had fewer specimen labeling errors. Also, 24/7 phlebotomy services were associated with lower specimen error rates. Establishing quality metrics for specimen labeling and deploying 24/7 phlebotomy operations may contribute to improving the accuracy of specimen labeling for the clinical laboratory.
PMID: 18834220 [PubMed - indexed for MEDLINE]
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Nontuberculous mycobacterial infections.
Arch Pathol Lab Med. 2008 Aug;132(8):1333-41
Authors: Jarzembowski JA, Young MB
CONTEXT: Nontuberculous mycobacteria include numerous acid-fast bacilli species, many of which have only recently been recognized as pathogenic. The diagnosis of mycobacterial disease is based on a combination of clinical features, microbiologic data, radiographic findings, and histopathologic studies. OBJECTIVE: To provide an overview of the clinical and pathologic aspects of nontuberculous mycobacteria infection, including diagnostic laboratory methods, classification, epidemiology, clinical presentation, and treatment. DATA SOURCES: Review of the pertinent literature and published methodologies. CONCLUSIONS: Nontuberculous mycobacteria include numerous acid-fast bacilli species, many of which are potentially pathogenic, and are classified according to the Runyon system based on growth rates and pigment production. Their slow growth hinders cultures, which require special medium and prolonged incubation. Although such methods are still used, newer nucleic acid-based technologies (polymerase chain reaction and hybridization assays) can rapidly detect and speciate some mycobacteria–most notably, distinguishing Mycobacterium tuberculosis from other species. Infections caused by these organisms can present as a variety of clinical syndromes, not only in immunocompromised patients but also in immunocompetent hosts. Most common among these are chronic pulmonary infections, superficial lymphadenitis, soft tissue and osteoarticular infections, and disseminated disease. Treatment of nontuberculous mycobacterial infections is difficult, requiring extended courses of multidrug therapy with or without adjunctive surgical intervention.
PMID: 18684037 [PubMed - indexed for MEDLINE]
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