The systemic immune-inflammation index (SIII) is a laboratory measure of immune-inflammatory activity.
Parameters:
(1) platelet count
(2) absolute neutrophil count
(3) absolute lymphocyte count
SIII =
= (platelet count) * (absolute neutrophil count) / (absolute lymphocyte count)
The SIII may be elevated in:
(1) relapse of an autoimmune disease
(2) progression or recurrence of a malignant neoplasm
One point of confusion is the units of measure.
If values are reported in 10^9/L, then
(1) a value >= 330 * 10^9 is considered high in patients with hepatocellular carcinoma (Hu et al).
(2) a value >= 572 * 10^9 is considered high in patients with solid tumors (Zhong et al).
If values are reported in 10^3/µL, then a value of 1,170 * 10^3 (or 11.7 * 10^5) is associated with relapse in polyarteritis nodosa (Kato et al).
A second point of confusion is determination before or after therapy. For cancer patients the pretreatment value may be more predictive.
