Topic Name

Message

If ARUP Consult does not answer your test selection and interpretation questions, or if you would like to suggest ways to improve content or usability, please send a message to the Consult editorial staff.

Please do not include any patient-specific or personal health information (PHI) in your message.

Email Address

An email address is not required, but providing one allows the ARUP Consult editorial staff to respond directly. ARUP will only use your email address to respond to your feedback. See the ARUP privacy policy for more information regarding email use.

CAPTCHA

What code is in the image?

Enter the characters shown in the image.

This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Prolonged Clot Time Reflexive Profile

3006383

Prolonged Clot Time Reflexive Profile 3006383

Method

Electromagnetic Mechanical Clot Detection/Immunoturbidimetry/Microlatex Particle-Mediated Immunoassay/Platelet Agglutination/Chromogenic Assay

Use to evaluate prolonged clotting times such as PT and/or aPTT when cause is unknown
Most useful for the workup of patients with unexpected prolonged clotting times
Condition-specific testing is preferred when the patient has a known coagulation disorder or a clear bleeding presentation
Reflexive panel includes basic clotting times (PT, aPTT, dilute Russell viper venom time [DRVVT]), lupus anticoagulant testing, fibrinogen, and d-dimer

Clotting time tests such as prothrombin time (PT) and/or activated partial thromboplastin time (aPTT) are commonly used for a variety of reasons, including workup of a bleeding tendency, as part of a presurgical evaluation, as guidance for blood product replacement, or to monitor anticoagulant medication. Prevalence of prolonged clotting time varies depending on the setting and on patient- and laboratory-specific factors. Prolonged clotting times of unclear etiology may require further evaluation to determine cause and to exclude clinically significant bleeding disorders. The Prolonged Clot Time Reflex Panel provides a comprehensive workup to determine the etiology of prolonged clotting times, including lupus anticoagulants and factor deficiencies or inhibitors. In rare circumstances in which a definitive cause for prolonged clotting time is not identified by testing available within the panel, appropriate follow-up testing will be recommended in the customized panel interpretation.

Typical Testing Strategy

Based on the patterns observed in this reflex test, additional studies may be recommended by ARUP Hemostasis/Thrombosis medical directors, such as coagulation factor assays and von Willebrand factor testing.

Disease Overview

Symptoms

Symptoms associated with prolonged clotting times depend on the underlying etiology.

Patients with an LA:
- May be asymptomatic or may have elevated thrombotic risk (if LA is associated with antiphospholipid syndrome)
- Generally are not at increased risk for bleeding
Patients with a factor deficiency or inhibitor are at increased risk for bleeding

Diagnostic Issues

This reflexive panel was designed to evaluate prolonged clotting times (as detected by tests such as PT and/or aPTT), particularly in presurgical or other settings where there is not strong clinical or other laboratory evidence that suggests a specific coagulation disorder
Panel benefits include:
- Greater standardization and cost-effectiveness in the assessment of prolonged clotting times
- More timely diagnosis and avoidance of multiple rounds of testing and multiple phlebotomies for the patient
- Expert interpretation by medical directors who supervise the lab performing the testing
A patient history form submitted with the test order allows for optimal panel interpretation and correlation with the clinical setting
Patients with a known coagulation disorder or strong clinical or other laboratory evidence of a specific coagulation disorder (such as a clear bleeding presentation) should be offered condition-specific testing

Physiology

Clotting times tests, such as PT and/or aPTT, enable evaluation of coagulation reactions and are dependent on:
- The presence and function of coagulation factors, including fibrinogen
- Phospholipid support for the coagulation reactions
- Calcium availability (affected by specimen collection tube/anticoagulant)
Problems with any of these components can result in clotting time prolongation

Test Interpretation

Results

Reflexive test selection and panel interpretation are performed by ARUP Hemostasis/Thrombosis medical directors
Customized panel interpretation includes the clinical significance of any abnormalities identified and recommendations for follow-up testing, if indicated
Reference intervals will be provided for each test performed, including age-stratified reference intervals, when appropriate

Limitations

Anticoagulant medications may interfere with testing and cause erroneous results
Recent transfusion or factor replacement may affect results
Results may be inaccurate in the event of inappropriate specimen collection and handling
- Clotted specimens (serum specimen or traumatic venipuncture)
- Line draws (specimen may be contaminated with heparin or IV fluids)
- Incorrect anticoagulant (anything other than sodium citrate plasma)

References

17605969

Kamal AH, Tefferi A, Pruthi RK. How to interpret and pursue an abnormal prothrombin time, activated partial thromboplastin time, and bleeding time in adults. Mayo Clin Proc. 2007;82(7):864-873.

25002009

Kruse-Jarres R, Singleton TC, Leissinger CA. Identification and basic management of bleeding disorders in adults. J Am Board Fam Med. 2014;27(4):549-564.

Feedback