Ordering Recommendation

Acceptable screening panel for common inherited thrombophilias.

Mnemonic
THROM COM
Methodology

Electromagnetic Clot Detection/Quantitative Enzymatic/Polymerase Chain Reaction/Fluorescence Monitoring

Performed

Sun-Sat

Reported

2-7 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation

Fasting preferred. Refer to Specimen Handling at aruplab.com for hemostasis/thrombosis specimen handling guidelines.

Collect

Lt. blue (sodium citrate) AND lavender (EDTA) or pink (K2EDTA) AND serum separator tube or green (sodium or lithium heparin).

Specimen Preparation

Serum Separator Tube or Green (sodium or lithium heparin) must be centrifuged and serum or plasma separated within 1 hour of collection. Transfer 1 mL centrifuged serum or plasma to ARUP Standard Transport Tube and label centrifuged tube for homocysteine testing. (Min: 0.5 mL) AND Transport two 2 mL aliquots platelet-poor plasma (sodium citrate) (Min: 1 mL/aliquot) AND Transport 5 mL whole blood (EDTA). (Min: 1 mL)

Storage/Transport Temperature

Light blue (sodium citrate):  CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.
Lavender whole blood and Serum or Green (sodium or lithium heparin): Refrigerated.

Unacceptable Conditions

Specimens collected in any tube type not listed above.

Remarks
Stability

Light blue (sodium citrate): Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 2 weeks
Lavender whole blood: Ambient: 2 hours; Refrigerated: 1 week; Frozen: Unacceptable
Serum or Green (sodium or lithium heparin):
Ambient: 1 hour; Refrigerated: 1 week; Frozen: 3 months

Reference Interval

Effective November 18, 2013

Test Number
Components
Reference Interval
0030235 Partial Thromboplastin Time 24-35 seconds
0030095 Factor VIII, Activity
Age Reference Interval
0-6 years 56-191%
7-9 years 76-199%
10-11 years 80-209%
12-13 years 72-198%
14-15 years 69-237%
16-17 years 63-221%
18 years and older 56-191%

0099869 Homocysteine, Total Less than 11 µmol/L, for both male and female
0056060 Prothrombin (F2) c.*97G>A (G20210A) Pathogenic Variant
0030127 APC Resistance Profile 2.0 or greater
  Factor V Leiden by PCR Negative: The sample is negative for factor V Leiden, R506Q mutation.

Interpretive Data

Ratios less than 2.00 suggest APC resistance. This method uses factor V deficient plasma; therefore, APC resistance due to a nonfactor V mutation will not be detected. Extreme factor V deficiency may cause abnormal ratio.  Elevated total homocysteine (tHcy) concentrations may be associated with vitamin B12 deficiency, folate deficiency, or inherited disorders of methionine metabolism. tHcy may also be used as a weak-graded risk factor for cardiovascular disease or stroke.

No compliance statements are in use for this test.

Note

If APC resistance is normal, then no further testing will be added. If APC resistance is abnormally low, then Factor V Leiden by PCR will be added. Additional charges apply.  False elevations of plasma or serum homocysteine may occur if the plasma or serum is not promptly separated from the cells at the time of collection.

Hotline History
N/A
CPT Codes

85730; 85240; 83090; 81240; 85307; if reflexed, add 81241

Components
Component Test Code* Component Chart Name LOINC
0030052 Thrombosis Interpretation 48767-8
0030095 Factor VIII, Activity 3209-4
0030193 APC Resistance 13590-5
0030194 Factor V Leiden by PCR 21668-9
0030235 Partial Thromboplastin Time 14979-9
0056060 Prothrombin (F2) G20210A Variant 24475-6
0099869 Homocysteine, Total 13965-9
2001308 FACV REF Specimen 31208-2
2001334 PT PCR Specimen 31208-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Activated Protein C Resistance
  • APC Resistance
  • APCR
  • F2 G20210A mutation
  • F8 Activity
  • Factor V Leiden
  • Factor V Leiden Functional Assay
  • Factor V Leiden PCR
  • Factor VIII, Activity
  • FVL
  • Hypercoag
  • Hypercoagulable Panel
  • Protein C Resistance
  • Prothrombin mutation
  • prothrombin time
  • PTT
  • total homocyteine
Thrombotic Risk, Inherited Etiologies (Most Common) with Reflex to Factor V Leiden