Test Catalog

Test ID: AMYPI    
Amyloid P (SAP) Immunostain, Technical Component Only

Useful For Suggests clinical disorders or settings where the test may be helpful

Identification of amyloid deposits in tissue

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Amyloid P (SAP) is a serum protein that is generally incorporated into the extracellular deposits of all amyloid types. Immunohistochemical staining for SAP produces diffuse, extracellular staining in positive tissues, and colocalizes with Congo Red apple-green birefringence. All types of amyloid should be positive for SAP. Immunohistochemical classification of amyloid has been largely replaced by subtyping using tandem mass spectrometry analysis on formalin-fixed paraffin-embedded specimens, due to its superior sensitivity and specificity.

Interpretation Provides information to assist in interpretation of the test results

This test includes only technical performance of the stain (no pathologist interpretation is performed). Mayo Clinic cannot provide an interpretation of tech only stains outside the context of a pathology consultation. If an interpretation is needed, refer to PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case. All material associated with the case is required. Additional specific stains may be requested as part of the pathology consultation, and will be performed as necessary at the discretion of the Mayo pathologist.


The positive and negative controls are verified as showing appropriate immunoreactivity and documentation is retained at Mayo Clinic Rochester. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request. Contact 855-516-8404.


Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen-dependent. Best practice is for paraffin sections to be cut within 6 weeks.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Jang B, Koh Y, Seo JW: Immunohistochemical classification of amyloid deposits in surgical pathology. Basic and Applied Pathology 2009;2:1-8

2. Schonland SO, Hegenbart U, Bochtler T, et al: Immunohistochemistry in the classification of systemic forms of amyloidosis: a systematic investigation of 117 patients. Blood 2012;119(2):488-493

3. Stewart CR, Haw A 3rd, Lopez R, et al: Serum amyloid P colocalizes with apolipoproteins in human atheroma: functional implications. J Lipid Res 2007;48:2162-2171