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Product FAQ

• Activated Protein C (APC)

  • Can I freeze the reagents in the Coatest APC resistance kits to prolong their stability?
  • Can I use Coatest APC Resistance V without the predilution with FV deficient plasma? Isn’t this just like using the APC R kit?
  • Describe the interaction between Protein S and APC.
  • Describe the protein C pathway and APC resistance. What is the relative risk of venous thrombosis for those who are APC resistant?
  • Explain the types of protein C deficiency, and the clinical manifestations.
  • How do factor V and VIII levels affect the Coatest APC Resistance tests?
  • What effect does variation of plasma levels of protein C have on the APC ratio?
  • What is the normal baseline range for the APTT reaction? What types of conditions might cause a patient to give abnormal aPT time, and what can be done about it?
  • Which assay should I run – Coatest APC Resistance or Coatest APC Resistance V?

• Antibodies (Abs)

  • Are the Affinity Biologicals antibodies available in solvents other than HBS-glycerol?
  • Aren't monoclonal antibodies always better than polyclonal antibodies?
  • I am interested in antibodies that will react or cross-react with hemostasis related proteins in other species. Will some of the antibodies raised to human antigens cross-react with the rabbit or rat counterparts?
  • What is meant by "whole IgG" and "affinity-purified" antibody formats?
  • What is provided in the VWF-EIA or other paired antibody products for ELISA? Are these actual kits?
  • What is the best concentration to use these antibodies for ELISA, immunoblotting and immunohistochemistry applications?
  • Why are ABI antibodies supplied in a solution of buffered glycerol. What are the practical implications of working with such a viscous solution?
  • Will these polyclonal antibodies recognize the unactivated, activated and complexed forms of my protein? What about recombinant constructs of protein fragments?

• Antiphospholipid

  • Define anti-phospholipid antibodies and anti-phospholipid antibody cofactor.
  • Describe a laboratory algorithm for testing for anticardiolipin antibodies.
  • Describe the anti-phospholipid Syndrome (APS), including the laboratory criteria for diagnosis.
  • Describe the location and function of the various phospholipids including: cardiolipin (CL), phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylcholine (PC), and phosphatidylinsitol (PI).
  • How does a syphilis infection affect the REAADS anti-cardiolipin test?
  • Is administering one test sufficient for diagnosis?
  • List some phospholipid cofactors.
  • Summarize the b2-Glycoprotein 1 test kit. What is the normal range?
  • Summarize the IgG/IgM and IgA anti-cardiolipin test. What is the normal range?
  • What are autoantibodies?
  • What are some features of the REAADS anti-Cardiolipin test? The b2GPI test?
  • What is the advantage of an assay for anti-phospholipid antibody cofactors over an assay for the antibody itself?
  • What is the clinical significance when samples test positive for the anti-cardiolipin antibodies and are negative for anti-b2GPI?
  • What is the role of Beta 2 Glycoprotein 1 (B2GP1) in anti-phospholipid antibody binding?

• Antithrombin (AT)

  • Can Coamatic Antithrombin be used to measure mouse plasma?
  • Coamatic Heparin is optimized for use with and without exogenous antithrombin. When is it recommended to add exogenous AT, and why?
  • Describe heparin’s interaction with antithrombin. Why is the anti-FXa method a better way to measure heparin activity?
  • Even though there is documentation that the anti-FXa method is better, how could a researcher determine antithrombin in plasma based on a thrombin method?
  • Explain the function of antithrombin and its interaction with thrombin and heparin?
  • Explain the types of antithrombin deficiency, and the clinical manifestations. What treatment options are available?
  • How should I make my standard pre-dilutions? It is not very clear from the package insert.
  • I am getting lower levels of antithrombin than expected. What could I be doing wrong?
  • What is the conversion factor for Antithrombin from IU to mg?
  • What is the difference between Coamatic Antithrombin and Coamatic AT 400 and Coamatic Antithrombin LR?
  • When exogenous AT is desired, how should it be added in the Coamatic Heparin test?
  • Why did Chromogenix discontinue Coatest Antithrombin and replace it with Coamatic Antithrombin?

• Apoptosis & Apoptosense

  • I have a very large number of samples to test, and I don't want to mess with a complicated assay.
  • I need an assay that is sensitive and robust.
  • Briefly describe the procedure for the M30-Apoptosense assay.
  • Can all cell types be used?
  • Can both serum and plasma samples be used?
  • Can components from different lot numbers be mixed?
  • Does hemolysis affect the levels of M30-Apoptosense measurements in a sample?
  • Does the assay measure caspase activity? What is the advantage or disadvantage to what it measures?
  • Does the M30-Apoptosense assay also measure necrosis?
  • How should samples be stored?
  • How specific is the assay with other species?
  • MCF-7 cells are known to be defective in caspase-3 activity. Can I still use the M30-Apoptosense assay?
  • The method I am using now does not distinguish between apoptotic, necrotic, and viable cells. How is the M30-Apoptosense different?
  • The methods I use measure the late stages of apoptosis. How is this product different?
  • What can the M30-Apoptosense assay be used for?
  • What does the M30-Apoptosense assay contribute that the Caspase-3 assay, or other caspase assays, does not?
  • What is the advantage of M30-Apoptosense relative to other methods?
  • What is the measurement theory behind the M30-Apoptosense assay?
  • What kind of samples can be analyzed?

• Bioreagents

  • Can the tPA activity standard be used to measure two-chain tPA or just single chain tPA?
  • Define a katal.
  • Define an enzyme and a substrate.
  • How can I measure prothrombin activity? What is considered an elevated level of prothrombin activity?
  • Is the plasminogen reagent Glu- or Lys- plasminogen?
  • The activity of plasmin and plasminogen is expressed in CU. What is this, and what is the equivalent in nkat?
  • The factor Xa reagent says it is 71 nkat, but I need to know what that is in g/ml and mol/ml.
  • The majority of the Chromogenix substrate library has an Arginine (Arg or R) group at the P1 position (the amino acid position that occurs at the preferred cleavage site). Why is this?
  • What is the 53 nkat vial of thrombin equivalent to in NIH units?

• Chromogenic Substrates

  • Can the tPA activity standard be used to measure two-chain tPA or just single chain tPA?
  • Define a katal.
  • Define an enzyme and a substrate.
  • How can I measure prothrombin activity? What is considered an elevated level of prothrombin activity?
  • I am looking for a chromogenic assay to measure TFPI activity. What substrates will work?
  • Is the plasminogen reagent Glu- or Lys- plasminogen?
  • The activity of plasmin and plasminogen is expressed in CU. What is this, and what is the equivalent in nkat?
  • The factor Xa reagent says it is 71 nkat, but I need to know what that is in g/ml and mol/ml.
  • The majority of the Chromogenix substrate library has an Arginine (Arg or R) group at the P1 position (the amino acid position that occurs at the preferred cleavage site). Why is this?
  • There are a few different substrates that are hydrolyzed by plasmin. If I want to use as short incubation times as possible, and need a selective substrate for plasmin, which should I choose?
  • What aspects must a scientist consider when choosing the best chromogenic substrate?
  • What if the reconstituted substrate has some precipitate or is cloudy?
  • What is a chromogenic substrate composed of?
  • What is a peptide? What is the difference between a tripeptide and a tetrapeptide? How are amino acids linked to form peptides?
  • What is the 53 nkat vial of thrombin equivalent to in NIH units?
  • Which substrate is best suited for measuring two-chain tPA, and why?
  • Why are the reactions measured at 405 nm?
  • Why is pNA the leaving group on all of the Chromogenix substrates?

• Factor VIII (FVIII)

  • If thrombin is formed, will it hydrolyze the substrate S-2765?
  • Can I use cryoprecipitate samples with the FVIII kits?
  • Does the Coatest FVIII detect animal plasma?
  • Is it OK to use glass tubes for the assay?
  • Sometimes when I run the Coamatic FVIII assay, I see an upward drift in my activity from the first to the last samples. Why is this?
  • The standard pre-dilutions for the Coatest FVIII assay don’t make sense to me. For example, to get 100%, I dilute 100 ml plasma with 50 ml buffer, but to get my 50% standard, I dilute 100 ml plasma with 200 ml buffer. Why?
  • We know that low levels of factor VIII activity constitutes hemophilia A, but are there any clinical manifestations of elevated factor VIII levels? How can a researcher measure elevated FVIII levels?
  • What are FVIII inhibitors, and how can I measure them?
  • What are some of the therapies researchers are looking at for the treatment of hemophilia A?
  • What are the latest recommendations for measuring potencies of high purity factor VIII concentrates?
  • What is the advantage of using the Coamatic FVIII over a clotting test?
  • What is the difference between Coamatic FVIII, Coatest FVIII, and Coatest FVIII:C/4?
  • What is the function of von Willebrand Factor? Briefly describe von Willebrand disease.
  • What is the measurement principle behind the FVIII chromogenic kits?
  • What should I do for standards and controls?
  • Who can benefit from using chromogenic factor VIII assays?
  • Why is thrombin added in the Coamatic FVIII factor reagent?

• Factor X (FX)

  • Do you have applications for the DiaPharma Factor X kit on automated coagulation analyzers?
  • What can I use for calibrators & controls?
  • What CPT code should I use?
  • What is the therapeutic range?
  • What is the utility of this kit? Am I expected to use this on ALL my Coumadin patients?
  • Why can’t I just use a FX clotting assay?

• Factor XIIa (FXIIa)

  • Can the AFecTa kit be used with animal plasma?
  • Define the following: (1) Lipoprotein, (2) low density lipoprotein, (3) very low density lipoprotein, (4) chylomicrons, (5) triglycerides.
  • Describe the AFT ELISA (AFecTa). What is the measurement range
  • How are AFT levels associated with risk of second myocardial infarction (MI) after treatment with a thrombolytic drug?
  • How is Factor XII activated?
  • How specific is the antibody?
  • What are some reasons for measuring AFT in plasma?
  • What are some strengths and weaknesses of the Axis-Shield AFT ELISA (AFecTa)?
  • What are the requirements for sample collection and storage?
  • What are the typical AFT concentrations in the following states: (1) normal, (2) diabetes, (3) renal failure, (4) CAD, (5) pregnancy, (6) ischemic stroke
  • What is activated Factor XII (AFT)?
  • What is atherosclerosis? What are statins?
  • What is factor XII?
  • What is lipoprotein lipase (LPL)?
  • What is the assay principle?
  • What is the normal concentration in human plasma?
  • What is the recovery of added AFT?
  • What is the recovery of added AFT?
  • What is the role of AFT in the coagulation cascade?
  • What is the role of AFT?
  • What is the total assay time?
  • What is the typical assay imprecision?
  • Who are some potential customers for AFT?
  • Why is cholesterol not a good predictor of CVD risk? What other markers of risk assessment are being researched?
  • Why measure AFT in plasma?

• Heparin (Hep)

  • Coamatic Heparin is optimized for use with and without exogenous antithrombin. When is it recommended to add exogenous AT, and why?
  • Compare hirudin with heparin. How can hirudin level be determined?
  • Describe heparin’s interaction with antithrombin. Why is the anti-FXa method a better way to measure heparin activity?
  • Do you have calibrators and controls for measuring unfractionated heparin?
  • How do the pharmacokinetics of LMW heparins differ from UF heparin, and what are the therapeutic ranges for each?
  • How does Protein C affect Coaliza Protein S – Free? What about heparin?
  • I am using the Coamatic Heparin on the MLA 1600, but am having trouble setting up the assay since there is no antithrombin diluent. What protocol should I be using?
  • I need an assay that complies with the USP monograph for the determination of heparin activity. What test kits are suitable?
  • I would like to run Coatest LMW heparin on the MLA 900. Do you have an application for this instrument?
  • In the Coatest Heparin package insert, the section “Limitations of the procedure” states that in some pathological states, plasma alone my hydrolyze S-2222, and that to determine the interference one should substitute FXa with an equal volume of buffer...
  • The dilution of the 0.1 IU/ml heparin solution in Coatest Heparin can cause some confusion. Please explain the Coatest Heparin standardization.
  • There has been debate about the advantages of low molecular weight heparin versus unfractionated heparin. Which of our kits can measure LMW heparin?
  • What is heparin-induced thrombocytopenia (HIT)? When HIT is suspected in a patient treated with UF heparin, should LMW heparin therapy replace UF therapy?
  • What is the difference between Coamatic Heparin, Coatest Heparin and Coatest Low Molecular Weight Heparin / Heparin?
  • When exogenous AT is desired, how should it be added in the Coamatic Heparin test?

• Plasmin Inhibitor

  • Define alpha2-antiplasmin?
  • Describe the measurement principle behind Coamatic Plasmin Inhibitor.
  • If a patient plasma is hemolytic or lipemic, how should I analyze it?
  • Is the plasmin in the Coamatic Plasmin Inhibitor the same as the plasmin reagent sold separately?
  • Is there any influence from alpha2-macroglobulin? If so, how can it be overcome?
  • What clinical situations are associated with decreased levels of plasmin inhibitor? Elevated levels?
  • What is the measurement principle behind Coamatic Plasminogen?
  • Will elevated levels of plasminogen interfere with the Coamatic Plasmin Inhibitor test?

• Plasminogen (Plg)

  • Define alpha2-antiplasmin?
  • Describe the structure and function of plasminogen.
  • Describe the types of plasminogen deficiency. What are the clinical conditions associated with decreased plasminogen levels? With elevated plasminogen levels?
  • Do I have to generate a standard curve for each run I perform?
  • How is plasminogen converted to plasmin?
  • What is the difference between Coamatic Plasminogen and the discontinued Coatest Plasminogen?
  • What is the difference between Glu-plasminogen and Lys-plasminogen? How can the two forms be measured?
  • What is the measurement principle behind Coamatic Plasminogen?
  • Which protocol should I use to run Coamatic Plasminogen on the MLA 1600?
  • Will elevated levels of plasminogen interfere with the Coamatic Plasmin Inhibitor test?

• Plasminogen Activator Inhibitor (PAI)

  • Describe some of the inhibitors to t-PA.
  • How does a specific gene polymorphism, PAI-1 4G genotype, relate to CVD risk?
  • What factors cause increased and decreased levels of t-PA and PAI?
  • What is the clinical importance of t-PA and PAI?
  • What is the difference between an ELISA test and a chromogenic test? Which of our kits uses which technology?
  • Won’t tPA be inhibited by PAI-1?

• Product Symbols & Markings

  • What do the kit symbols and markings mean?

• Protein C (ProC)

  • Can I freeze the reagents in the Coatest APC resistance kits to prolong their stability?
  • Can I use Coatest APC Resistance V without the predilution with FV deficient plasma? Isn’t this just like using the APC R kit?
  • Describe the protein C pathway and APC resistance. What is the relative risk of venous thrombosis for those who are APC resistant?
  • Describe the Protein C pathway. What are some APC cofactors?
  • Explain the types of protein C deficiency, and the clinical manifestations.
  • How does Protein C affect Coaliza Protein S – Free? What about heparin?
  • In the Coamatic® Protein C assay, what substances could interfere with the assay, how will they affect results, and what can be done to overcome the interference?
  • What effect does variation of plasma levels of protein C have on the APC ratio?
  • What is the clinical significance of Protein S?
  • What is the normal baseline range for the APTT reaction? What types of conditions might cause a patient to give abnormal aPT time, and what can be done about it?

• Protein S (ProS)

  • Are elevated levels of Protein S clinically significant?
  • Briefly describe the complement system, including the role of C4BP (C4b-binding protein).
  • Describe the interaction between Protein S and APC.
  • Describe the Protein C pathway. What are some APC cofactors?
  • Describe the structure of C4BP.
  • Differentiate between the types of protein S deficiency.
  • Explain the interaction between Protein S and C4b-binding protein.
  • How does Coaliza Protein S compare with REAADS Protein S? How do they differ?
  • How does Protein C affect Coaliza Protein S – Free? What about heparin?
  • How is functional activity of protein S tested?
  • What are some benefits to Coaliza Protein S – Free?
  • What is the clinical significance of Protein S?
  • What is the measurement principle behind Coaliza Protein S – Free?
  • What is the measurement principle behind REAADS Monoclonal Free Protein S ELISA?

• Tissue Plasminogen Activator (t-PA)

  • According to recent research, what is the proper time frame after a stroke to administer t-PA?
  • Describe some of the inhibitors to t-PA.
  • Explain the function of t-PA.
  • What factors cause increased and decreased levels of t-PA and PAI?
  • What is the clinical importance of t-PA and PAI?
  • What is the difference between an ELISA test and a chromogenic test? Which of our kits uses which technology?
  • What is the difference between single and two-chain tPA?
  • Won’t tPA be inhibited by PAI-1?