(Medicare National Coverage Determinations Manual)

Limitations   1. The PTT is not useful in monitoring the effects of warfarin on a patients coagulation routinely.  However, a PTT may be ordered on a patient being treated with warfarin as heparin therapy is being discontinued.  A PTT may also be indicated when the PT is markedly prolonged due to warfarin toxicity.  2. The need to repeat this test is determined by changes in the underlying medical condition and/or dosing of heparin.   3. Testing prior to any medical intervention associated with a risk of bleeding and thrombosis (other than thrombolytic therapy) will generally be considered medically necessary only where there are signs or symptoms of a bleeding or thrombotic  abnormality or a personal history of bleeding, thrombosis or a condition associated with a coagulopathy.  Hospital/clinical -specific policies, protocols, etc., in and of themselves, cannot alone justify coverage.   190.17 - Prothrombin Time (PT)  (Rev. 17, Issued: 07 -02-04) (Effective/Implementation: Not Applicable) PM AB -02-110  Basic plasma coagulation function is readily assessed with a few simple laboratory tests:  the partial thromboplastin time (PTT), PT, thrombin time, or a quantitative fibrinogen determination.  The PT test is one in -vitro laboratory test used to assess coagulation.  While the PTT assesses the intrinsic limb of the coagulation system, the PT assesses the extrinsic or tissue factor dependent pathway.  Both tests also evaluate the common coagulation pathway involving all the reactions that occur after the activation of factor X.   Extrinsic pathway factors are produced in the liver and their production is dependent on adequate vitamin K activity.  Deficiencies of factors may be related to  decreased production of increased consumption of coagulation factors.  The PR/INR is most commonly used to measure the effect of warfarin and regulate its dosing.  Warfarin blocks the effect of vitamin K on hepatic production of extrinsic pathway factors.  A PT is expressed in seconds and/or as an international normalized ration (INR).  The INR is the PT ration that would result if the WHO reference thromboplastin had been used in performing the test.  Current medical information does not clarify the role of laboratory PT testing in patients who are self monitoring.  Therefore, the indications for testing apply regardless of whether or not the patient is also PT self -testing.   Indications   1. A PT may be used to assess patients taking warfarin.  The PT is generally not useful in monitoring patients receiving heparin who are not taking warfarin.  2. A PT may be used to assess patients with signs or symptoms of abnormal bleeding or thrombosis.  For example: swollen extremity with or without prior trauma; unexpla ined bruising; abnormal bleeding, hemorrhage, or hematoma; petechiae or other signs or thrombocytopenia that could be due to disseminated intravascular coagulation.  3. A PT may be useful in evaluating patients who have a history of a condition known to be as sociated with the risk of bleeding or thrombosis that is related to the extrinsic coagulation pathway.  Such abnormalities may be genetic or acquires.  For example: dysfibrinogenemia; afibrinogenemia (complete); acute or chronic liver dysfunction or failur e, including Wilsons disease and hemochromatosis; disseminated intravascular coagulation (DIC); congenital and acquired deficiencies of factors II, V, VII, X; vitamin K deficiency; lupus erythematosus; hypercoagulable state; paraproteinemia; lymphoma; amyloidosis; acute and chronic leukemias; plasma cell dyscrasia; HIV infection; malignant neoplasms; hemorrhagic fever; salicylate poisoning; obstructive jaundice; intestinal fistula; malabsorption syndrome; colitis; chronic diarrhea; presence of peripheral v enous or arterial thrombosis or pulmonary emboli or myocardial infarction; patients with bleeding or clotting tendencies; organ transplantation; presence of circulating coagulation inhibitors.  4. APT may be used to assess the risk of hemorrhage or thrombosis  in patients who are going to have a medical intervention known to be associated with increased risk of bleeding or thrombosis.  For example: evaluation prior to invasive procedures or operations of patients with personal history of bleeding of a condition associated with coagulopathy; prior to the use of thrombolytic medication.  Limitations   1. When an ESRD patient is tested for PT, testing more frequently than weekly requires documentation of medical necessity, e.g., other than chronic renal failure or rena l failure unspecified.   2. The need to repeat this test is determined by changes in the underlying medical condition and/or the dosing of warfarin.  In a patient on stable warfarin therapy, it is ordinarily not necessary to repeat testing more than every two to three weeks.  When testing is performed to evaluate a patient with signs or symptoms of abnormal bleeding or thrombosis and the initial test result is normal, it is ordinarily not necessary to repeat testing unless there is a change in the patients medical status.   3. Since the INR is a calculation, it will not be paid in addition to the PT when expressed in seconds, and is considered part of the conventional PT test.   4. Testing prior to any medical intervention associated with a risk of bleeding and thrombosis (other that thrombolytic therapy) will generally be considered medically necessary only where there are signs or symptoms of a bleeding or thrombotic abnormality of a personal history of bleeding, thrombosis or a condition associated with a coagulopathy.  Hospital/clinic -specific policies, protocols, etc., in and of themselves, cannot alone justify coverage.   190.18 - Serum Iron Studies  (Rev. 17, Issued: 07- 02-04) (Effective/Implementation: Not Applicable) PM AB -02-110  Serum iron studies are useful in the evaluation of disorders of iron metabolism, particularly iron deficiency and iron excess.  Iron studies are best performed when the patients is fasting in the morning and has abstained form medications that may influenc e iron balance.   Iron deficiency is the most common cause of anemia. In young children on a milk diet, iron deficiency is often secondary to dietary deficiency.  In adults, iron deficiency is usually the result of blood loss and is only occasionally secondary to dietary deficiency or malabsorption.  Following major surgery the patient may have iron deficient erythropoiesis for months or years if adequate iron replacement has not been given.  High doses of supplemental iron may cause the serum iron to be elevated.  Serum iron may also be altered in acute and chronic inflammatory and neoplastic conditions.  Total iron binding capacity (TIBC) is an indirect measure of transferring, a protein that binds and transports iron.  TIBC quantifies transferring by the a mount of iron that it can bind.  TIBC and transferrin are elevated in iron deficiency, and with oral contraceptive use, and during pregnancy.  TIBC and transferrin may be decreased in malabsorption syndromes or in those affected with chronic diseases.  The  percent saturation represents the ratio of iron to the TIBC.   Assays for ferritin are also useful in assessing iron balance.  Low concentrations are associated with iron deficiency and are highly specific.  High concentrations are found in hemosiderosis ( iron overload without associated tissue injury) and hemochromatosis (iron overload with associated tissue injury).  In these conditions the iron is elevated, the TIBC and transferring are within the reference range or low, and the percent saturation is elevated.  Serum ferritin can be useful for both initiating and monitoring treatment for iron overload.   Transferrin and ferritin belong to a group of serum proteins known as acute phase reactants, and are increased in response to stressful or inflammatory co nditions and also can occur with infection and tissue injury due to surgery, trauma or necrosis.  Ferritin and iron/TIBC (or transferrin) are affected by acute and chronic inflammatory conditions, and in patients with these disorders, tests of iron status may be difficult to interpret.   Indications   1. Ferritin, iron and either iron binding capacity or transferrin are useful in the differential diagnosis or iron deficiency, anemia and for iron overload conditions.   a. The following presentations are examples that may support the use of these studies for elevating iron deficiency:  Certain abnormal blood count values (i.e., decreased mean corpuscular volume (MCV), decreased hemoglobin/hematocrit when the MCV is low or normal, or increased red cell dist ribution with width (RDW) and low or normal MCV); abnormal appetite (pica); acute or chronic gastrointestinal blood loss; hematuria; menorrhagia; malabsorption; status post- gastrectomy; status port -gastrojejunostomy; malnutrition; preoperative autologous blood collection(s); malignant, chronic inflammatory and infectious conditions associated with anemia which may present in a similar manner to iron deficiency anemia; following a significant surgical procedure where blood loss had occurred and had not been repaired with adequate iron replacement.   b. The following presentations are example that may support the se of these studies for evaluating iron overload:  chronic hepatitis; diabetes; hyperpigmentation of skin; arthropathy; cirrhosis; hypogonadism; hypopituitarism; impaired porphyrin metabolism; heart failure; multiple transfusions; sideroblastic anemia; thalassemia major; cardiomyopathy, cardiac dysrhythmias and conduction disturbances.  2. Follow -up testing may be appropriate to monitor response to therapy, e .g., oral or parenteral iron, ascorbic acid, and erythropoietin.  3. Iron studies may be appropriate in patients after treatment for other nutritional deficiency anemia, such as folate and vitamin B12, because iron deficiency may not be revealed until such a nutritional deficiency is treated.   4. Serum ferritin may be appropriate for monitoring iron status in patients with chronic renal disease with or without dialysis.   5. Serum iron may also be indicated for evaluation of toxic effects of iron and other metals (e. g., nickel, cadmium, aluminum, lead) whether due to accidental, intentional exposure or metabolic causes.   Limitations   1. Iron studies should be used to diagnose and manage iron deficiency or ion overload states.  These tests are not to be used solely to assess acute phase reactants where disease management will be unchanged.  For example, infections and malignancies are asso ciated with elevations in acute phase reactants such as ferritin, and decreases in serum iron concentration, but iron studies would only be medically necessary if results or iron studies might alter the management of the primary diagnosis or might warrant direct treatment of an iron disorder or condition.   2. If a normal serum ferritin level is documented, repeat testing would not ordinarily be medically necessary unless there is a change in the patients condition, and ferritin assessment is needed for the on going management of the patient.  For example, a patient presents with new onset insulin- dependent diabetes mellitus and has a serum ferritin level performed for the suspicion of hemochromatosis.  If the ferritin level is normal, the repeat ferritin for di abetes mellitus would not be medically necessary.   3. When an end stage renal disease (ESRD) patient is tested for ferritin, testing more frequently than every three months requires documentation of medical necessity (e.g., other than chronic renal failure or  renal failure, unspecified).   4. It is ordinarily not necessary to measure both transferring and TIBC at the same time because TIBC is an indirect measure of transferrin.  When transferrin is ordered as part of the nutritional assessment for evaluating malnu trition, it is not necessary to order other iron studies unless iron deficiency or iron overload is suspected as well.   5. It is not ordinarily necessary to measure both iron/TIBC (or transferrin) and ferritin in initial patient testing.  If clinically indica ted after evaluation of the initial iron studies, it may be appropriate to perform additional iron studies either on the initial specimen of on a subsequently obtained specimen.  After a diagnosis of iron deficiency or iron overload is established, either iron/TIBC (or transferring) or ferritin may be medically necessary for monitoring, but not both.  6. It would not ordinarily be considered medically necessary to do a ferritin as a preoperative test except in the presence of anemia or recent autologous blood collections prior to the surgery.   190.19 - Collagen Crosslinks, Any Method  (Rev. 17, Issued: 07- 02-04) (Effective/Implementation: Not Applicable) PM AB -02-110  Collagen crosslinks, part of the matrix of bone upon which bone mineral is deposited, are biochemical markers the excretion of which provides a quantitative measurement of bone resorption.  Elevated levels of urinary collagen crosslinks indicate elevated bone resorption.  Elevated bone resorption contributes to age -related and postmenopausal loss of bone leading to osteoporosis and increased risk of fracture.  The collagen crosslinks assay can be performed by immunoassay or by high performance liquid chroma tography (HPLC).  Collagen crosslink immunoassays measure the pyridinoline crosslinks and associated telopeptides in urine.