The mixing test is a medical laboratory study used to clarify the differential diagnosis of clotting abnormalities. Other names for the test include mixing studies, PT mixing study, PTT mixing study, circulating anticoagulant screening test, or inhibitor screen.
The test is most often initiated when a patient has an abnormally long prothrombin time (PT) or more usually, a prolonged partial thromboplastin time (PTT), to distinguish whether the underlying problem is a clotting factor deficiency on the one hand, or a factor inhibitor on the other hand.
The test relies on the fact that the circulaing level sof any coagulation factor must be reduced to a level significantly less than 50% in order to affect the PT or PTT. Thus when the patient's blood is mixed with an equal volume of blood donated by a person known to have normal clotting, the mixture (which will have at least 50% factor activity for all factors) will clot more quickly if the intial disorder was because of a deficiency, while it will not clot any faster if the initial disorder was because of a factor inhibitor.
If the PTT of the mixed blood is normal, factor deficiency is indicated, and further testing will be performed for specific factors. If the PTT of the mixed blood is still prolonged, an inhibitor is suggested, and further studies (typically starting with an assay for lupus anticoagulant) will be performed. This result, however, can also be seen if the patient is taking heparin or another anticoagulant. If the PTT of the mixed blood initially normalized, but becomes prolonged again after a two hour incubation, the test is suggestive of a factor VIII inhibitor (because their effect requires this amount of time to become effective). When a mixing test shows this result, a factor VIII inhibitor assay will be performed.
Colored Micro-Surfacing shall consist of mixing a synthetic bitumen emulsion, pigment, aggregate, additives, and water and spreading the mixture on a surface or pavement where shown on the plans, as specified in these specifications and the special provisions, and as directed by the Engineer.
The laboratory test results shall be provided in a report and shall be signed by the laboratory that performed the tests and mix design and shall show the results of the tests on individual materials, comparing the test results to those required by the specifications.
A job mix design shall be submitted by the Contractor for approval by the Engineer that conforms to the specification limits, and that is suitable for the traffic, climate conditions, curing conditions and final use.
A third, less common type of test, mixes a sample of urine in several tubes or cups with a powder or liquid to cause a chemical reaction.
If you do the test as soon as you have missed a period and the results show you are not pregnant (negative results), repeat the test in 1 week if your menstrual period has not started, or have a pregnancy test done at your health professional's office or a clinic.
For a chemical mixingtest, you collect a sample of urine in a cup or well, then add it to one or more test tubes that have a chemical powder or liquid.
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