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The recognition of molecular marker events leading to hemostatic and thrombotic disorders and technologic advances in molecular biology and immunology has added a new dimension in the diagnosis of bleeding and thrombotic disorders. Pathophysiologic activation of coagulation, fibrinolysis, kallikrein-kinin system, vascu— lar stress, and intercellular interactions result in the generation of cell/process specific markers of a pathophysiologic event. It has been two decades since the concept of molecular markers was first introduced in the diagnosis of hemostatic and thrombotic disorders. However, due to cost/technologic limitations and lack of understanding of this field at various levels its usage in clinical laboratory diagnosis was rather limited. With the advent of such analytical techniques such as enzyme-linked immunosorbent assays (ELISA) a disease specific molecular profiling can be readily accomplished. Subclinical activation of platelets, endothelial distress, and aberrations of the protease network can be readily diagnosed by utilizing specific assays. The concept of hypercoagulable state is now validated utilizing such markers of hemostatic activation such as platelet factor 4, thromboxane B2, fibrinopeptide A and plasminogen activator inhibitor. Cardiovascular disease risk and blood vascular disorders can be diagnosed utilizing these markers. The monitoring of antithrombotic drugs that do not produce any anticoagulant effects on blood can also be readily accomplished by using some of these lanalytes. Using specific monoclonal antibodies, various diagnostic profiles for such disorders as thrombotic stroke, disseminated intravascular coagulation, primary fibrinolysis, hemodynamic disorders, and diseases of vascular origin can be investigated. Since the introduction of this concept some 50 additional markers have been introduced. The recognition of tissue factor pathway inhibitor (TFPI) has introduced a new concept in the understanding of the plasmatic and vascular interactions. Tissue factor and its inhibitor can now be measured at fmol amounts in plasma and body fluids. Specific antibodies to these markers can also be utilized in immunocytometric and flow cytometric analysis and will provide valuable diagnostic information. High through-put instruments and cost/technologies compliance methodologies are available to provide affordable laboratory approaches in the new era of cost constraint diagnostic medicine. However, a major deficit in the educational programs still exists and warrants the development of these programs in medical and allied health curriculums. Key Words: Molecular markers—Hypercoagulable state—Enzyme-linked immunosorbent assay—Tissue factor pathway inhibitor— Tissue factor.

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Hemolysis in serum specimens is commonplace. This study examines the effect of hemolysis on results of selected chemical assays. Hemolysis was simulated by adding hemolysate to serum to give hemoglobin concentrations of 90 to 2800 mg/liter and a rating by technologists of 0 to 4 + hemolyzed. The effect of hemolysis on values for some serum constituents, particularly acid phosphatase and creatine kinase, was shown to be method dependent. Not unexpectedly, hemolysis most affects results for lactate dehydrogenase.

A woman with hyperthyroidism and myasthenia gravis developed respiratory failure in association with radiation-induced thyroiditis. Treatment with steroids, propylthiouracil, propranolol, iodine, and plasmapheresis was associated with dramatic reduction in serum triiodothyronine (T3), serum thyroxine (T4), and thyroglobulin levels and prompt recovery of the patient. The medications that this patient received have been shown to cause an abrupt decline in serum T3 levels with little or no effect on the serum T4 concentration. The 56% decline in serum T4 observed in this patient during the first 24 hours of therapy suggests that plasmapheresis may be a useful adjunct to medical therapy in selected patients with severe hyperthyroidism.

We have developed automated assays for antithrombin III for use with the Gilford 3500 and the Multistat Microcentrifugal Analyzer. The assays are two-stage kinetic-rate methods and involve use of human thrombin and the chromogenic peptide substrate S-2238. The reagents are prepared in-house from commercially available components. Both automated methods have good precision and results correlate well with both an established chromogenic substrate assay and an immunological assay. The automated assays offer the advantages of speed, sensitivity, high throughput, and low reagent consumption and are useful for both routine work and high-volume testing in clinical studies and screening programs.

Vol. 26 p 1386, Table 5, column 3, entry two should read "71 ± 26," not "17 ± 26." p 1933, under the heading Notes, change first sentence to read "...equal to the numerical value of the molar..." Vol. 27 p 202, The last equation for sT2 should read: 5W2 + SD2 [n(k - 1)]/(kn - 1) p 204, col. 2, fourth full paragraph "25 mg/L" should read "25 g/L" Because of a postal delay, one paper was printed without the authors' corrections, which are: p 287, para. 1, fifth line "Theoretical...," insert the word "and" after "alternates." Table 1, column 4: last entry should read "+7.57(0.974)"; column 5: first entry should read "±6.5." Amend title of Table 2 to read "Quantitative Performance of Second- and Fourth-Derivative Assays for Paraquat Dichloride Extracted from Horse Serum," and change "hight" to "higher" in footnote a. p 288, under "Procedure," in two places the words "setting the instrument on" should be changed to "using as reference." p 289, under "Aqueous...," in first paragraph, fourth line, delete ",dissolved" and insert "solution." In the next paragraph delete the words "is used...satellite" and insert instead "measure (to the long-wavelength satellite) is used." In the fourth line of the first paragraph in column 2, change "is" to "in." p 290, line 10 under "Discussion": correct spelling is "Åkerblom." p 297, In the equation, E is activity of the enzyme in serum at time t, less the basal activity. p 317, In first sentence of "Discussion," the binding constants should be 1010 to 1011 L/mol. p 343: The following Table was inadvertently omitted from the Letter See table in PDF file p 422, Under "Reagents," dilute the 4 mL of D-glucarate solution with 16 (not 46) mL of 10 mmol/L HCl. p 425, Table 4, last column should read: 5.07 (1.72) and 5.06 (1.55). p 508, See Letter.