Coombs', Direct
| Coombs', Direct | | | |
| Number | | 006270 |
| CPT | | 86880 |
| Synonyms | | DAT ; Direct Antiglobulin Test ; Direct Antihuman Globulin Test ; Direct Coombs' |
| Test Includes | | Direct Coombs' with polyspecific Coombs' serum. Red cells found to be positive are further tested with monospecific Coombs' sera (anti-IgG and anticomplement). |
| Specimen | | Whole blood |
| Volume | | 4 mL |
| Minimum Volume | | 0.5 mL |
Container | | Lavender-top (EDTA) tube or yellow-top (ACD) tube |
| Storage Instructions | | Specimens should be tested as soon as possible or within 72 hours of collection. Samples that cannot be tested immediately should be stored at 2°C to 8°C. Do not freeze. |
| Causes for Rejection | | Gross hemolysis; bacterial or other contamination; specimen more than 5 days old |
| Reference Interval | | Negative |
| Use | | Detect in vivo coating of IgG and/or complement components on RBCs |
| Limitations | | The presence of potent cold autoagglutinins may interfere with test interpretation. Testing performed using clotted blood specimens may yield false-positive results with anticomplement. |
| Methodology | | Antiglobulin test |
| Additional Information | | Positive direct Coombs' tests are associated with a variety of conditions which include hemolytic transfusion reaction, autoimmune hemolytic anemia, hemolytic disease of the newborn, and may be secondary to certain pathological conditions or drug therapy. Note: The presence of a positive direct Coombs' test does not absolutely correlate with a pathological condition. |
| References | | Technical Manual, 15th ed, Bethesda, MD: American Association of Blood Banks, 2005. |
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