Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 51

Given the following results, calculate the IgG index: CSF IgG,

50 mg/dL; serum IgG, 2 g/dL; CSF albumin, 70 mg/dL;

serum albumin, 5 g/dL.

A. 0.6

B. 6.0

C. 1.8

D. 2.8

The CSF IgG index calculated in Study Question 27 indicates:

A. Synthesis of IgG in the CNS

B. Damage to the blood–brain barrier

C. Cerebral hemorrhage

D. Lymphoma infiltration

Step 1 of 2

CSF (Cerebrospinal fluid) IgG index:

It is used to calculate synthesis of immunoglobulin G (IgG) within central nervous system (CNS).

Formula to compute the IgG index is given below,

Where,

CSF - Cerebrospinal fluid in mg/dL (milligrams per deciliter)

• Generally, IgG index values above 0.70 indicate production of IgG within CNS

• In study question 27, CSF IgG index is 1.8 that indicates IgG synthesis in CNS

Therefore, CSF IgG index 1.8 indicates “IgG synthesis CNS”. Hence, the correct answer is option.