CPT® Code 85611

Official Description

Prothrombin time; substitution, plasma fractions, each

Common Language Description

Prothrombin time (PT) is a critical laboratory test that measures the duration it takes for blood to clot. This test specifically evaluates the functionality of prothrombin, also known as factor II, which is a vital clotting factor synthesized by the liver. The production of adequate prothrombin levels is dependent on sufficient vitamin K, which plays a crucial role in the synthesis of several clotting factors. The prothrombin time test is instrumental in diagnosing various conditions related to abnormal bleeding or bruising, monitoring the effectiveness of anticoagulant therapy, particularly with medications like warfarin (Coumadin), and assessing the levels of essential blood-clotting factors, including factors I, II, V, VII, and X. Additionally, it serves to evaluate vitamin K levels and liver function, providing insights into how efficiently the body utilizes its clotting factors. The test employs electromagnetic mechanical clot detection to ascertain the clotting time. In cases where the prothrombin time is found to be elevated and the patient is not undergoing anticoagulant therapy, a follow-up test known as a prothrombin time mixing study may be conducted. This involves mixing the patient's plasma with normal plasma in a 1:1 ratio, incubating the mixture, and measuring the clotting time again. The results of this mixing study can help determine whether the patient has an inhibitor, such as lupus anticoagulant, or a coagulation factor deficiency. The CPT® code 85611 is utilized to report each prothrombin time mixing study performed, ensuring accurate documentation and billing for this essential diagnostic procedure.

1. Indications

The prothrombin time (PT) test, specifically when utilizing CPT® code 85611 for substitution plasma fractions, is indicated for several clinical scenarios, including:

Abnormal Bleeding or Bruising - The test is performed to help identify the underlying causes of unexplained bleeding or bruising in patients.
Monitoring Anticoagulant Therapy - It is used to check the effectiveness of blood-thinning medications, such as warfarin (Coumadin), ensuring that patients are within the therapeutic range.
Assessment of Coagulation Factors - The test helps evaluate for low levels of critical blood-clotting factors, including factors I, II, V, VII, and X, which are essential for proper coagulation.
Vitamin K Levels - It is utilized to check for deficiencies in vitamin K, which is necessary for the synthesis of several clotting factors.
Liver Function Evaluation - The prothrombin time test aids in assessing liver function by determining how quickly the body is utilizing its clotting factors.

2. Procedure

The procedure for conducting a prothrombin time mixing study, as described by CPT® code 85611, involves several critical steps:

Step 1: Sample Collection - A blood sample is drawn from the patient, typically from a vein in the arm, using standard venipuncture techniques. This sample will be used to obtain the patient's plasma for testing.
Step 2: Plasma Separation - The collected blood sample is processed to separate the plasma from the cellular components. This is usually achieved through centrifugation, which spins the blood at high speeds to separate the components based on density.
Step 3: Mixing with Normal Plasma - The patient's plasma is then mixed with an equal volume of normal plasma in a 1:1 ratio. This mixture is crucial for determining whether the patient's coagulation issues are due to an inhibitor or a deficiency in clotting factors.
Step 4: Incubation - The mixed plasma is incubated for a specified period to allow for any potential interactions between the patient's plasma and the normal plasma to occur.
Step 5: Clotting Time Measurement - After incubation, the clotting time of the mixture is measured using electromagnetic mechanical clot detection. This measurement will indicate whether the clotting time has normalized or remained prolonged.
Step 6: Result Interpretation - The results are analyzed to determine if the clotting time corrects with the addition of normal plasma. If the clotting time normalizes, it suggests a coagulation factor deficiency; if it does not, it may indicate the presence of an inhibitor, such as lupus anticoagulant.

3. Post-Procedure

After the prothrombin time mixing study is completed, the patient may experience no significant post-procedure care requirements, as the test is minimally invasive. However, it is essential to monitor the patient for any immediate adverse reactions to the blood draw, such as bruising or discomfort at the venipuncture site. The results of the test will be documented and communicated to the healthcare provider, who will interpret the findings in the context of the patient's clinical situation. Further management or additional testing may be recommended based on the outcomes of the prothrombin time mixing study.

Short Descr	PROTHROMBIN TEST
Medium Descr	PROTHROMBIN TIME SUBSTITUTION PLASMA FRCTJ EACH
Long Descr	Prothrombin time; substitution, plasma fractions, each
Status Code	Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days	XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC)	9 - Not Applicable
Multiple Procedures (51)	9 - Concept does not apply.
Bilateral Surgery (50)	9 - Concept does not apply.
Physician Supervisions	09 - Concept does not apply.
Assistant Surgeon (80, 82)	9 - Concept does not apply.
Co-Surgeons (62)	9 - Concept does not apply.
Team Surgery (66)	9 - Concept does not apply.
Diagnostic Imaging Family	99 - Concept Does Not Apply
CLIA Waived (QW)	No
APC Status Indicator	Conditionally packaged laboratory tests
Type of Service (TOS)	5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS)	T1H - Lab tests - other (non-Medicare fee schedule)
MUE	2
CCS Clinical Classification	233 - Laboratory - Chemistry and Hematology

91	Repeat clinical diagnostic laboratory test: in the course of treatment of the patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91. note: this modifier may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required. this modifier may not be used when other code(s) describe a series of test results (eg, glucose tolerance tests, evocative/suppression testing). this modifier may only be used for laboratory test(s) performed more than once on the same day on the same patient.
90	Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
59	Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
GW	Service not related to the hospice patient's terminal condition