Comparison of diagnostic accuracy of antibodies to free light chains and conventional antibodies to light chains in 46 renal biopsies, compared with final diagnosis of any renal abnormality related to light chain disorders, including neoplastic infiltration
| Antibodies to free light chains | |
|---|---|
| Deposition | No deposition |
| 29 | 17 |
| Abnormality/no abnormality | Abnormality/no abnormality |
| 28/1* | 4†/13 |
| Sensitivity 88%, specificity 93% | |
| Conventional antibodies to light chains | |
|---|---|
| Deposition | No deposition |
| 20 | 26 |
| Abnormality/no abnormality | Abnormality/no abnormality |
| 20/0 | 12‡/14 |
| Sensitivity 63%, specificity 100% | |
Difference in sensitivity (free light chain antibodies – conventional antibodies)=25% (95% CI 9% to 41%); difference in specificity (free light chain antibodies – conventional antibodies)=−7% (95% CI −14% to 0%).
*κ & AA deposition in AA amyloid.
†No deposition in AL amyloid (2), neoplastic infiltration (2).
‡No deposition in AL amyloid (8), cryoglobulinaemic glomerulonephritis (2), light chain deposition disease (1), neoplastic infiltration (1).