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Test Code IGG4I IgG4 Immunostain, Technical Component Only

Reporting Name

IgG4 IHC, Tech Only

Useful For

Identification of IgG4-positive plasma cells in the tissue of patients with systemic autoimmune or allergic manifestations

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
IHTOI IHC Initial, Tech Only No No
IHTOA IHC Additional, Tech Only No No

Testing Algorithm

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).

Method Name

Immunohistochemistry (IHC)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

TECHONLY


Ordering Guidance


This test includes only technical performance of the stain (no pathologist interpretation is performed). If diagnostic consultation by a pathologist is required order PATHC / Pathology Consultation.



Shipping Instructions


Attach the green "Attention Pathology" address label (T498) and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.



Specimen Required


Specimen Type: Tissue

Supplies: Immunostain Technical Only Envelope (T693)

Container/Tube: Immunostain Technical Only Envelope

Preferred:

-Formalin-fixed, paraffin-embedded tissue block

OR

-2 Unstained, positively charged glass slides (25- x 75- x 1-mm) per test ordered; sections 4-microns thick

Acceptable: None


Specimen Stability Information

Specimen Type Temperature Time Special Container
TECHONLY Ambient (preferred)
  Refrigerated 

Reject Due To

Wet/frozen tissue 
Cytology smears 
Nonformalin fixed tissue 
Nonparaffin embedded tissue 
Noncharged slides 
ProbeOn slides 
Snowcoat slides 		 Reject 

Day(s) Performed

Monday through Friday

CPT Code Information

88342-TC, primary

88341-TC, if additional IHC

LOINC Code Information

Test ID Test Order Name Order LOINC Value
IGG4I IgG4 IHC, Tech Only 77202-0

 

Result ID Test Result Name Result LOINC Value
70783 IgG4 IHC, Tech Only Bill only; no result

Secondary ID

70472

Clinical Information

Immunoglobulin G4 is the least abundant of IgG subclasses, normally comprising 6% of total IgG. Elevated serum IgG4 levels may be associated with localized or systemic allergic and autoimmune manifestations, such as inflammatory pseudotumor in liver, breast, and lung, sclerosing pancreatitis, and pemphigus vulgaris. In these disease states, increased numbers of IgG4-positive plasma cells are present in the tissue.

Interpretation

This test does not include pathologist interpretation, only technical performance of the stain. If interpretation is required, order PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case.

 

The positive and negative controls are verified as showing appropriate immunoreactivity. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request; call 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

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.

 

The charge of glass slides can be affected by environmental factors and subsequently may alter slide staining. Sending unsuitable glass slides can result in inconsistent staining due to poor slide surface chemistry.

 

Best practices for storage of positively charged slides:

-Minimize time slides are stored after being unpackaged

-Limit exposure to high humidity and heat

-Minimize exposure to plastics

Clinical Reference

1. Heidarpour M, Rajabi P, Pour EB, Fayyazi E. Immunohistochemistry for immunoglobulin G4 in the diagnosis of pemphigus. Indian J Dermatol. 2019;64(4):338. doi:10.4103/ijd.IJD_87_18

2. Chen LYC, Mattman A, Seidman MA, Carruthers MN. IgG4-related disease: what a hematologist needs to know. Haematologica. 2019;104(3):444-455. doi:10.3324/haematol.2018.205526

3. Miyabe K, Zen Y, Cornell LD, et al. Gastrointestinal and extra-intestinal manifestations of IgG4-related disease. Gastroenterology. 2018;155(4):990-1003.e1. doi:10.1053/j.gastro.2018.06.082

4. Magaki S, Hojat SA, Wei B, So A, Yong WH. An introduction to the performance of immunohistochemistry. Methods Mol Biol. 2019;1897:289-298. doi:10.1007/978-1-4939-8935-5_25

Method Description

Immunohistochemistry on sections of paraffin-embedded tissue.(Unpublished Mayo method)

Report Available

1 to 3 days

Specimen Retention Time

Until staining is complete.

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763)

-Renal Diagnostics Test Request (T830)