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Official Description

Antihuman globulin test (Coombs test); indirect, each antibody titer

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The indirect antihuman globulin test, commonly known as the Coombs test, is a laboratory procedure utilized to identify clinically significant antibodies present in a patient's blood. This test is particularly important in the context of blood transfusions, as it helps ensure compatibility between donor and recipient blood. In this test, certain red blood cells may become coated with complement proteins or IgG antibodies, which prevents them from agglutinating, or clumping together, when subjected to centrifugation. This phenomenon is referred to as IgG or complement sensitization. To facilitate agglutination, an additional antibody that reacts with the IgG or complement must be introduced into the test environment. The indirect antihuman globulin test is conducted on in vitro specimens, meaning that the blood sample is analyzed outside of the body. During the procedure, the specimen is incubated at a controlled temperature of 37 degrees Celsius, allowing the antibodies in the serum to interact with the red blood cells. Following this incubation, the cells are washed to remove unbound antibodies, and an antiglobulin reagent is applied to detect any antibody coating on the cells. The cells are then centrifuged, and the results of the test are interpreted based on the degree of agglutination observed. It is important to note that for qualitative testing performed on each reagent red cell, the CPT® code 86885 should be used, while CPT® code 86886 is designated for each antibody titer performed, which assesses the strength or potency of identified antibodies.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The indirect antihuman globulin test (Coombs test) is performed for several specific indications, primarily related to the detection of antibodies that may pose a risk during blood transfusions or pregnancy. The following conditions warrant the use of this test:

  • Blood Transfusion Compatibility This test is essential for determining the presence of clinically significant antibodies in a patient’s blood prior to receiving a blood transfusion, ensuring that the transfused blood will not elicit an adverse immune response.
  • Hemolytic Disease of the Newborn The test is utilized to assess the risk of hemolytic disease in newborns, particularly in cases where the mother has developed antibodies against fetal red blood cells.
  • Autoimmune Hemolytic Anemia It is indicated in the evaluation of patients suspected of having autoimmune hemolytic anemia, where the body produces antibodies against its own red blood cells.
  • Monitoring Antibody Levels The test is also performed to monitor the levels of specific antibodies in patients who have previously been identified with such antibodies, particularly in the context of ongoing treatment or management of blood disorders.

2. Procedure

The procedure for conducting the indirect antihuman globulin test involves several critical steps to ensure accurate results. Each step is designed to facilitate the detection of antibodies in the serum that may coat red blood cells.

  • Step 1: Specimen Collection A blood sample is collected from the patient, typically using venipuncture. The specimen must be handled carefully to prevent contamination and ensure the integrity of the sample for testing.
  • Step 2: Incubation The collected serum is then incubated at 37 degrees Celsius. This temperature is optimal for allowing any antibodies present in the serum to react with the red blood cells in vitro, promoting the sensitization process.
  • Step 3: Washing the Cells After incubation, the red blood cells are washed to remove any unbound antibodies. This step is crucial as it helps to isolate the cells that have been sensitized by the antibodies, ensuring that the subsequent detection step is accurate.
  • Step 4: Application of Antiglobulin Reagent An antiglobulin reagent is then added to the washed cells. This reagent is designed to bind to any antibodies that are coating the red blood cells, facilitating the agglutination process.
  • Step 5: Centrifugation The mixture is subjected to centrifugation, which helps to separate the agglutinated cells from the supernatant. This step is essential for visualizing the results of the test.
  • Step 6: Reading the Results Finally, the test is read to determine the presence and degree of agglutination. The results indicate whether clinically significant antibodies are present in the patient’s serum.

3. Post-Procedure

After the indirect antihuman globulin test is completed, the results are analyzed and reported to the healthcare provider. If clinically significant antibodies are detected, further testing may be required to identify the specific antibodies present. This may include additional antibody identification tests or crossmatching procedures to ensure safe blood transfusions. Patients may be monitored for any adverse reactions if they are undergoing transfusions based on the test results. It is also important for healthcare providers to document the findings and any subsequent actions taken in the patient's medical record to maintain comprehensive care and compliance with clinical guidelines.

Short Descr COOMBS TEST INDIRECT TITER
Medium Descr ANTIHUMAN GLOBULIN INDIRECT EACH ANTIBODY TITER
Long Descr Antihuman globulin test (Coombs test); indirect, each antibody titer
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 STV-Packaged Codes
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 3
CCS Clinical Classification 235 - Other Laboratory
26 Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 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.
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.
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.
Date
Action
Notes
2011-01-01 Changed Short description changed.
2008-01-01 Changed Code description changed.
1993-01-01 Added First appearance in code book in 1993.
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Description
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