A combination of compositions of immune globulin and a soluble hyaluronidase for use for treating an IG-treatable disease or condition in a subject, wherein: the IG and soluble hyaluronidase are formulated separately for subcutaneous administration; the IG and soluble hyaluronidase are formulated for single dosage administration once a month; the soluble hyaluronidase is administered separately from the IG prior to administration of the IG and at the same site as the IG; the concentration of IG is 5 to 15% w/v and the amount of IG in the composition is 0.5 grams (g) to 70 g; the IG is formulated in a volume of liquid that is 50 mL to 700 mL; the soluble hyaluronidase is formulated for administration as a ratio of hyaluronidase to IG of 10 U/gram (g) to 500 U/g of IG, whereby the amount of hyaluronidase in the composition is sufficient to effect increased bioavailability of the IG when administered in combination with the IG to at least 90% of the bioavailability of the same single dosage of IG administered via intravenous administration for treatment of the same IG-treatable disease or condition; the soluble hyaluronidase is formulated in a volume of liquid that is 5 to 30 mL; and the IG-treatable disease or condition is selected from among immunodeficiency; acquired hypogammaglobulinemia secondary to hematological malignancies; Kawasaki's disease; chronic inflammatory demyelinating polyneuropathy (CIDP); Guillain-Barre Syndrome; Idiopathic thrombocytopenic purpura; inflammatory myopathies; Lambert-Eaton myasthenic syndrome; multifocal motor neuropathy; Myasthenia Gravis; Moersch-Woltmann syndrome; secondary hypogammaglobulinaemia, including iatrogenic immunodeficiency; specific antibody deficiency; Acute disseminated encephalomyelitis; ANCA-positive systemic necrotizing vasculitis; Autoimmune haemolytic anaemia; Bullous pemphigoid; Cicatricial pemphigoid; Evans syndrome, including autoimmune haemolytic anaemia with immune thrombocytopenia; Foeto-maternal/neonatal alloimmune thrombocytopenia (FMAIT/NAIT); Haemophagocytic syndrome; High-risk allogeneic haemopoietic stem cell transplantation; IgM paraproteinaemic neuropathy; kidney transplantation; multiple sclerosis; Opsoclonus myoclonus ataxia; Pemphigus foliaceus; Pemphigus vulgaris; Post-transfusion purpura; Toxic epidermal necrolysis/Steven Johnson syndrome (TEN/SJS); Toxic shock syndrome; Alzheimer's Disease; Systemic lupus erythematosus; multiple myeloma; sepsis; B cell tumors; trauma; and a bacterial, viral or fungal infection. the IG and soluble hyaluronidase are formulated separately for subcutaneous administration; the IG and soluble hyaluronidase are formulated for single dosage administration once a month; the soluble hyaluronidase is administered separately from the IG prior to administration of the IG and at the same site as the IG; the concentration of IG is 5 to 15% w/v and the amount of IG in the composition is 0.5 grams (g) to 70 g; the IG is formulated in a volume of liquid that is 50 mL to 700 mL; the soluble hyaluronidase is formulated for administration as a ratio of hyaluronidase to IG of 10 U/gram (g) to 500 U/g of IG, whereby the amount of hyaluronidase in the composition is sufficient to effect increased bioavailability of the IG when administered in combination with the IG to at least 90% of the bioavailability of the same single dosage of IG administered via intravenous administration for treatment of the same IG-treatable disease or condition; the soluble hyaluronidase is formulated in a volume of liquid that is 5 to 30 mL; and the IG-treatable disease or condition is selected from among immunodeficiency; acquired hypogammaglobulinemia secondary to hematological malignancies; Kawasaki's disease; chronic inflammatory demyelinating polyneuropathy (CIDP); Guillain-Barre Syndrome; Idiopathic thrombocytopenic purpura; inflammatory myopathies; Lambert-Eaton myasthenic syndrome; multifocal motor neuropathy; Myasthenia Gravis; Moersch-Woltmann syndrome; secondary hypogammaglobulinaemia, including iatrogenic immunodeficiency; specific antibody deficiency; Acute disseminated encephalomyelitis; ANCA-positive systemic necrotizing vasculitis; Autoimmune haemolytic anaemia; Bullous pemphigoid; Cicatricial pemphigoid; Evans syndrome, including autoimmune haemolytic anaemia with immune thrombocytopenia; Foeto-maternal/neonatal alloimmune thrombocytopenia (FMAIT/NAIT); Haemophagocytic syndrome; High-risk allogeneic haemopoietic stem cell transplantation; IgM paraproteinaemic neuropathy; kidney transplantation; multiple sclerosis; Opsoclonus myoclonus ataxia; Pemphigus foliaceus; Pemphigus vulgaris; Post-transfusion purpura; Toxic epidermal necrolysis/Steven Johnson syndrome (TEN/SJS); Toxic shock syndrome; Alzheimer's Disease; Systemic lupus erythematosus; multiple myeloma; sepsis; B cell tumors; trauma; and a bacterial, viral or fungal infection.