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Direct and Indirect Antibody Anti-C3b, C3d: Test Tube

Anti-IgG: Gel Method

Performing Laboratory

St. Luke's Hospital Cedar Rapids

Specimen Requirements


Preferred: Pink-top (EDTA) tube

Acceptable:  Lavender-top (EDTA) tube
Specimen Volume: 1 mL of EDTA whole blood

Stability: An EDTA, hand labeled, specimen drawn within 3 days of testing is the

               preferred specimen.  The sample should be tested as soon as possible

               following collection.  If a delay in testing occurs, the sample should be stored 2-6 C.   
Collection Instructions: If the specimen is to be used for transfusion purposes is must

                                        be correctly hand labeled from the armband with patient's full name,

                                       inpatient hospital medical record number or B-Band number, time/date

                                      collected and tech code/initials.

Note: Pregnancy, transfusion, and medication history may be required for interpretation.

Reference Values


Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

86850-Antibody screen

86880-Antiglobulin, direct

Useful For

The direct antiglobulin test is used to demonstrate the presence or absence of immunoglobulin (IgG or complement) on the surface of red blood cells.  Cells that have immunoglobulin adsorbed to their surfaces are said to be sensitized.  The direct antiglobulin test shows whether or not red blood cells have become sensitized in vivo.


The antibody screen test is used in the detection of unexpected blood group antibodies.