Overview: Complement Factor H Antibody (CFH Ab) TestIntroduction: The Complement Factor H Antibody Test detects antibodies to complement factor H, linked to kidney diseases causing swelling or blood in urine. Aligned with 2023 ASN guidelines, it uses an immunoassay for high specificity, aiding in autoimmune screening. This test is critical for guiding diagnosis, treatment, and improving outcomes in immunology for patients with suspected kidney diseases.
Other Names: CFH Antibody Assay, Kidney Autoimmune Test.
FDA Status: Laboratory-developed test (LDT), meeting immunology standards for diagnostic accuracy.
Historical Milestone: Complement factor H antibody testing began in the 2000s with kidney disease research. Immunoassays emerged in the 2010s, improving diagnostic accuracy for autoimmune kidney conditions.
Purpose: Diagnoses kidney diseases linked to complement dysregulation, guides treatment, and monitors antibody levels in patients with swelling or hematuria.
Test Parameters: 1. Complement Factor H Antibody
Pretest Condition: No fasting required. Collect serum or saliva at any time. Report symptoms like swelling or hematuria, and list medications like immunosuppressants.
Specimen: 2-5 mL serum (SST) or 1-2 mL saliva (sterile container). Centrifuge serum within 1 hour. Transport in a biohazard bag within 8 hours.
Sample Stability at Room Temperature: 8 hours
Sample Stability at Refrigeration: 7 days
Sample Stability at Frozen: 6 months
Medical History: Document swelling, hematuria, or family history of kidney diseases. Include current medications, especially immunosuppressants or steroids.
Consent: Written consent required, detailing the tests purpose, diagnostic implications, and potential need for immunosuppressive therapy.
Procedural Considerations: Uses an immunoassay to measure complement factor H antibodies. Results are available in 1-2 days, enabling rapid clinical decisions.
Factors Affecting Result Accuracy: Immunosuppressants may suppress antibody levels, causing false negatives. Hemolysis or improper storage can degrade samples.
Clinical Significance: Positive results confirm complement-mediated kidney disease, prompting immunosuppressive therapy. Negative results may require genetic testing.
Specialist Consultation: Consult a nephrologist for result interpretation. A rheumatologist referral is advised for autoimmune involvement.
Additional Supporting Tests: C3/C4 complement tests, kidney biopsy, or urinalysis to confirm kidney disease or assess complement dysregulation.
Test Limitations: False negatives may occur with early disease or immunosuppression. Results require clinical correlation.
References: ASN Kidney Disease Guidelines, 2023; Kidney International, Goodship TH, 2022.
