CLINICAL PATHOLOGY LABORATORY
February 25, 2000
NEW COAGULATION TESTS AND PANELS NEW
OUR GOALS
- More comprehensive coagulation testing on individual patients
- Improved diagnostic value
- Little or no increase in cost
- Introduce new coagulation tests (quantitative fibrinogen, D-dimer)
- Simplify and minimize sample requirements for coag testing
NEW COAGULATION PANELS
| Panel |
Cost |
Tests Included |
| Basic Coag Panel |
$30.00 |
PT, PTT, fibrinogen* |
| DIC Panel |
$40.00 |
PT, PTT, fibrinogen* D-dimer* (dog) or FDP (other species) |
| ATIII (with a panel) |
$25.00 |
Add ATIII to either panel for a reduced price (no add'l specimen needed) |
*New test! See below for a description
SPECIMEN REQUIREMENTS
Contact the lab prior to drawing the samples
For all test except FDP:
- Fill ONE (1) citrated blue top tube (3.0 ml or NEW 1.8 ml size)
- DO NOT SHORT-FILL CITRATE TUBES (will cause erroneous results!)
- Deliver to the lab ON ICE
For FDP:
- Obtain FDP tube from the lab
- Place 2 ml of blood in tube (do NOT place on ice) and deliver to lab
INDIVIDUAL TESTS
All tests can also be ordered individually
| Fibrinogen |
citrate tube on ice |
$15 |
| D-dimer |
citrate tube on ice |
$15 dogs only |
| PT |
citrate tube on ice |
$15 |
| PTT |
citgrate tube on ice |
$15 |
| PIVKA |
citrate tube on ice |
$15 |
| ATIII |
citrate tube on ice |
$39 dogs, cats, horses |
| FDP |
special tube from lab |
$15 any species |
NEW TESTS AND THEIR INTERPRETATION
QUANTITATIVE FIBRINOGEN TEST
A functional assay based on the thrombin time, accurate for detecting hypofibrinogenemia (unlike the heat precipitation method) as well as hyperfibrinogenemia. Hypofibrinogenemia occurs in DIC and other disorders associated with fibrinolysis, such as severe hepatic insufficiency, neoplasia, sepsis, and pancreatitis. Hereditary fibrinogen deficiencies are rare causes of low or absent fibrinogen.
Reference Intervals: (tentative, to be updated)
| Dogs |
90-255 mg/dl |
| Cats |
55-300 mg/dl |
| Horses |
65-18 mg/dl |
| Cattle |
60-233 mg/dl |
| Goats |
100-400 mg/dl |
Heat precipitation fibrinogen test will no longer be included in canine and feline CBC, but may be ordered as an individual test when indicated. The heat precipitation method is accurate for detecting hyperfibrinogenemia, and will continue to be included in large animal and avian/reptile CBC as a sensitive indicator of inflammation. In dogs and cats, hyperfibrinogenemia may occur in some coagulopathies (although hypofibrinogenemia is more common) and in chronic inflammation.
D-DIMER TEST
D-dimer is a degradation product of cross-linked fibrin, and a more sensitive and specific indicator of fibrinolysis than FDP. The assay is antibody-dependent and valid for use only in dogs. Plasma D-dimer concentration is markedly increased in DIC, and may be increased in deep vein thrombosis, pulmonary embolism, postsurgically, and in subclinical hypercoagulable states such as pregnancy. Although the D-dimer test is useful in the diagnosis of DIC in dogs, there is little data on expected results in other disease conditions; therefore, it may be helpful to concurrently measure FDP in some cases.
Test Interpretation:
Negative: Normal; does not support DIC or hypercoagulability
Positive:
- If patient has other laboratory and clinical evidence of DIC, a positive d-dimer test confirms this diagnosis (sensitivity 100%, specificity vs healthy dogs 97%). It is important to interpret results in light of other laboratory findings.
- If there is insufficient laboratory and clinical evidence of DIC (eg, thrombocytopenia, prolonged PTT, PT, hemorrhage), a positive D-dimer result may be false positive (in which case FDP results should be negative) or may indicate a subclinical hypercoagulable state of unknown clinical significance. The specificity of d-dimer concentrations in dogs with systemic diseases other than DIC has not been determined.