D-Dimer, Quantitative

Test Code: D-DI

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Useful For

The D-dimer test is useful for exclusion (but not diagnosis) of acute deep vein thrombosis (DVT) or pulmonary embolism (PE).

Specimen Requirements

Fasting Required	Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
No	Whole Blood, Plasma	3.2% Citrated Blue Top Tube (BTT)Citrated Blue Top Tube (BTT)		1.0 mL Platelet Poor Plasma	0.5 mL Platelet Poor Plasma

Collection Processing Instructions

-Citrated Blue Top Tube (BTT) must be drawn to the fill line.

-Completely invert tube three or four times to mix. Do Not Shake.

-Centrifuge tube at 3000 rpm for 10 minutes or Stat Spin for 3 minutes at 8500 rpm with the brake OFF as soon

as possible after collection.

-If testing cannot be performed within specimen stability transfer plasma (avoiding platelet contamination) to

polypropylene tube with plastic pipette for storage within two hours of collection.

-If sending to another testing location: If combined with other coag testing send only one frozen,

plasma aliquot (1mL) for all tests, with specimen label. Also send original Blue Top Tube (BTT) in case sample needs to be checked for clot.

Specimen Stability Information

Specimen Type	Temperature	Time
Whole Blood	Ambient	4 Hours
Whole Blood	Refrigerated	24 Hours
Plasma	Ambient	4 hours
	Refrigerated	24 hours
	Frozen (-20°C)	2 Weeks
	Frozen (-70°C)	6 Months

Rejection Criteria

Reject at gross hemolysis
Specimens filled below the fill line
Clotted
Specimens with abnormal results that have a Hct >55% that have not had the citrate anticoagulant adjusted

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Analytical Time	Methodology/Instrumentation
Diagnostic Treatment Center	Monday through Sunday	2-4 hours	Immunoassay/Sysmex CS-2500
Eau Claire	Monday through Sunday	2-4 hours	Immunoassay/Sysmex CS-2500
Flambeau Hospital	Monday through Sunday	2-4 hours	Immunoassay/Sysmex CS-2500
Ladysmith Medical Center	Monday through Sunday	2-4 hours	Immunoassay/Sysmex CA-620
Lakeview Medical Center	Monday through Sunday	2-4 hours	Immunoassay/Sysmex CS-2500
Marshfield	Monday through Sunday	Less than 2 hours	Immunoassay/Sysmex CS-2500
Merrill	Monday through Friday	2-4 hours	Optical Clot Detection/Sysmex CA-660
Minocqua	Monday through Sunday	2-4 hours	Immunoassay/Sysmex CS-2500
Neillsville	Monday through Sunday	2-4 hours	Immunoassay/Sysmex CS-2500
Stevens Point	Monday through Friday	2-4 hours	Optical Clot Detection/Sysmex CA-660
Wausau	Monday through Sunday	2-4 hours	Immunoassay/Sysmex CS-2500
Wisconsin Rapids	Monday through Friday	2-4 hours	Optical Clot Detection/Sysmex CA-660

Reference Range Information

Performing Location	Reference Range
Marshfield	< 190 - 499 ng/mL

Interpretation

An elevation of D-dimer (>500 ng/mL) indicates activation of coagulation with formation and degradation of cross-linked fibrin. It is a very sensitive, albeit very nonspecific, marker of pulmonary embolism (PE) or deep venous thrombosis (DVT). The main value of D-dimer testing in the setting of possible PE or DVT is its negative rule-out capability. A negative D-dimer result, when the pre-test probability of PE or DVT is low to intermediate, essentially excludes PE and DVT. In healthy adults D-dimer levels increase in a linear fashion after age 50. Based on current literature**, by optimizing the cutoffs with age, the very high sensitivity of the test can be maintained while providing greater specificity. This allows a greater percentage of older adults to be ruled-out. This allows a simple calculation of AGE x 10 for patients over 50 years old. For example, a 65 year-old patient would now have a cutoff of < 650 ng/mL (i.e. values of 650 ng/mL or less considered negative).

**Righini M, Van Es J, Exter D, et al. Age-Adjusted D-Dimer Cutoff Levels to Rule Out Pulmonary Embolism The ADJUST-PE Study. JAMA. 2014;311:1117.

**Raja AS, Greenberg JO, Qaseem A. Evaluation of Patients With Suspected Acute Pulmonary Embolism: Best Practice Advice From the Clinical Guidelines Committee of the American College of Physicians. Ann Intern Med. 2015;163:701.

Outreach CPTs

CPT	Modifier (if needed)	Quantity	Description	Comments
85379

Ordering Applications

Ordering Application	Description
Centricity	D-Dimer
Cerner	D-Dimer
COM	D-Dimer-Blood

If the ordering application you are looking for is not listed, contact your local laboratory for assistance.

Specimen Requirements

Fasting Required	Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
No	Whole Blood, Plasma	3.2% Citrated Blue Top Tube (BTT)Citrated Blue Top Tube (BTT)		1.0 mL Platelet Poor Plasma	0.5 mL Platelet Poor Plasma

Collection Processing