Cutoff Values of Serum IgG4 and Histopathological IgG4+ Plasma Cells for Diagnosis of Patients with IgG4-Related Disease

Table 2

Serum IgG and IgG4 concentrations and IgG4/IgG4 ratio of patients with false-positive and false-negative diagnoses of IgG4-RD.

False positives
Diagnosis	IgG (mg/dL)	IgG4 (mg/dL)	IgG4/IgG
(1) MCD	7,080	4,560	64.4%
(2) MCD	4,420	690	15.6%
(3) B-cell lymphoma	2,510	456	18.2%
(4) MCD	2,960	295	10.0%
(5) MCD	2,476	295	11.9%
(6) B-cell lymphoma	4,010	271	6.8%
(7) Scleritis	2,900	232	8.0%
(8) Sarcoidosis	1,380	189	13.7%
(9) Sjögren’s syndrome	3,920	171	4.4%
(10) Malignant lymphoma	1,930	141	7.3%
False negatives
Diagnosis	IgG(mg/dL)	IgG4(mg/dL)	IgG4/IgG
(1) IgG4-RD	1,149	125	10.9%
(2) IgG4-RD	1,210	123	10.2%
(3) IgG4-RD	1,228	111	9.0%
(4) IgG4-RD	1,260	106	8.4%

IgG4-RD: IgG4-related disease; MCD: multicentric Castleman’s disease.