| Coagulation Disorders Associated with Liver Failure |
| Monday, 05 September 2011 | {sidebar id=6}
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The liver is the major site of synthesis of almost all coagulation factors, except for Factor VIII and vWF. Liver failure is associated with decreased coagulation factors, decreased or dysfunctional platelets, dysfibrinogenemia and fibrinolysis. Patients with severe liver disease have lower levels of those coagulation factors synthesized by the liver. Inadequate vitamin K absorption may occur as a result of decreased bile acid secretion into the intestine, leading to a reduction in coagulation factors II, VII, IX and X. Abnormal forms of fibrinogen may be produced causing dysfibrinogenemia. Inhibitors of fibrinolysis, such as alpha-2 antiplasmin, are also decreased. Tissue plasminogen activator (TPA), which is produced by the endothelium and metabolized by the healthy liver, is elevated. Decreased alpha-2 antiplasmin and increased TPA cause fibrinolysis and hypofibrinogenemia. Platelet count may be decreased due to inadequate marrow production, sequestration associated with hypersplenism or consumption by low grade disseminated intravascular coagulation (DIC). Some patients may undergo liver transplantation. During reperfusion of the grafted liver, there is a further deterioration in coagulation due to endothelial cell injury in the donor organ, leading to further release of plasminogen activators. Additionally, heparin-like activity can be detected in the blood of many patients in the post-reperfusion phase of liver transplantation, even when there is no known source of exogenous heparin. Reperfusion coagulopathy resolves as graft function improves. Post liver transplantation, the imbalance shifts towards hypercoagulability, especially in children, due to exposure of tissue factor (TF) resulting from traumatic injury to a large capillary bed, venous stasis during clamping of the portal vein and inferior vena cava, ischemic insult to the intestines, activator release from the grafted liver, and blood transfusion. All of these coagulation factor abnormalities can be monitored in a clinical laboratory with a thromboelastograph (TEG).
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| Sunday, 24 July 2011 | {sidebar id=6}
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Patients with celiac disease produce several antibodies including gliadin, endomysial, tissue transglutaminase (tTG), and reticulin. IgA antibodies usually predominate, but IgG antibodies are also synthesized. New tests for deamidated gliadin IgA and IgG have replaced the older gliadin antibody tests. Sensitivity and specificity of deaminated gliadin antibodies for untreated celiac disease is comparable to tTg antibodies.
Inova Diagnostics has recently introduced a new screening test that simultaneously detects IgA and IgG antibodies to tissue transglutaminase (tTG) and deaminated gliadin peptide (QUANTA Lite® h-tTG/DGP Screen). The latter peptide is believed to be the immunodominant antigen in gluten. Deamination of gliadin by the enzyme tissue transglutaminase exposes specific B-cell epitopes. Studies have demonstrated that the sensitivity and specificity of deaminated gliadin antibodies for diagnosis of celiac disease are higher than unmodified gliadin and comparable to tTG antibodies. Antibody levels correlate with severity of enteropathy.
Two percent of patients with celiac disease will be IgA deficient and unable to make IgA antibodies. Because the new test detects both IgA and IgG antibodies, it allows for the detection of celiac disease even with coexistent IgA deficiency.
Approximately one year ago, our laboratory replaced a panel of individual tests with the Inova Celiac Screen. Gastroenterologists have been highly satisfied with its performance and report excellent correlation with small bowel biopsy results. |
| PNA FISH Improves Antibiotic Stewardship |
| Friday, 01 July 2011 | {sidebar id=6}
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Our laboratory partnered with pharmacy to create an antibiotic stewardship program in 2003. Laboratory began sending culture and sensitivity reports to pharmacy twice a day. A pharmacist called the attending physician and recommended antibiotic therapy modifications. This program expedited appropriate antibiotic therapy by approximately 18 hours.
PNA FISH from AdvanDx was introduced in January 2009. S. aureus/CNS PNA FISH allowed microbiologists to rapidly differentiate Stapylococcus aureus from coagulase- negative staphylococci. E. faecalis/OE PNA FISH was introduced in July 2009 and GNR Traffic Light PNA FISH in April 2010. These kits allowed us to identify 63% of all blood cultures on the same day that they turned positive. The average time for bacterial identification decreased from 132 to 38 hours. By immediately sending this information to pharmacy, the average antibiotic dose per patient decreased from 5.8 to 2.8 and the average cost for laboratory tests and antibiotics decreased from $72 to $18 per patient. The addition of PNA FISH greatly enhanced antibiotic stewardship within the health system. This is a perfect example of how laboratory and pharmacy can work together to improve patient care and decrease downstream health care costs.
More detailed information about this technology is available in the article entitled, “Peptide Nucleic Acid FISH for Blood Culture Identification”, located in the Test Interpretation section. Also see, http://www.advandx.com |
| Sunday, 22 May 2011 | {sidebar id=6}
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The latest designer drugs are being marketed as bath salts in head shops and on the Internet. Some popular names include Zoom, White Rush, Cloud Nine, Sextasy, White Dove and Ocean Snow. They have no legitimate use for bathing and are intended for substance abuse. These products contain stimulant compounds such as 3,4-methylene-dioxypyrovalerone (MDPV) or 4-methylmeth-cathinone (mephedrone). Users have snorted, injected and ingested these products. No relationship has been found between exposure route and severity of illness. Clinical findings are consistent with exposure to stimulants and include hypertension, tachycardia, tremors, mydriasis, agitation, delusions, hallucinations, paranoia and rhabdomyolysis. Fatalities have occurred.
Testing for these stimulants is available in the toxicology laboratories. Most patients abusing bath salts have tested positive for other drugs. Therefore, physicians should also order a urine drug screen. |
| More Transfusion Lectures on YouTube |
| Sunday, 08 May 2011 | {sidebar id=6}
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Four more Powerpoint presentations are available on YouTube. These lectures were entitled, "Cases That Kept Me Up at Night". The case studies discuss the following topics: - Fetal transfusion for combined HDN and FNAIT.
- Acute hemolysis in a trauma patient
- HBV from transfusion
- Transfusion of patient with WAIHA
- TRALI
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