Median (range) M-protein concentration and measures of free light chains year by year prior to multiple myeloma diagnosis
| Blood draw prior to multiple myeloma diagnosis, y . | M-protein concentration* (g/dL) . | Involved FLC-ratio† . | Involved-uninvolved FLC concentration,† mg/dL . | Involved FLC concentration,† mg/dL . | ||
|---|---|---|---|---|---|---|
| n . | Median (range) . | n . | Median (range) . | Median (range) . | Median (range) . | |
| By year | ||||||
| 2 | 24 | 1.6 (0.4-3.7) | 23 | 12.1 (2.3-138.4) | 7.8 (0.6-61.9) | 8.5 (0.9-62.3) |
| 3 | 47 | 1.3 (0.5-3.1) | 46 | 10.7 (1.7-285.7) | 7.3 (0.6-118.2) | 8.3 (1.0-119.0) |
| 4 | 37 | 1.1 (0.5-3.9) | 30 | 11.3 (1.8-1428.0) | 5.1 (0.6-326.8) | 6.1 (0.9-327.0) |
| 5 | 26 | 1.2 (0.6-3.8) | 25 | 12.5 (1.7-4042.6) | 9.0 (0.6-322.9) | 9.2 (1.5-323.0) |
| 6 | 20 | 1.2 (0.6-3.6) | 19 | 14.3 (1.7-907.5) | 10.7 (0.6-205.8) | 11.1 (1.5-206.0) |
| 7 | 11 | 1.3 (0.7-3.5) | 11 | 32.6 (1.8-677.9) | 12.9 (0.9-180.7) | 14.0 (2.0-181.0) |
| 8 or more | 10 | 0.9 (0.5-1.8) | 8 | 19.4 (2.6-107.1) | 12.0 (1.8-32.7) | 13.0 (3.0-33.0) |
| Trend test | P = .025 | P = .35 | –‡ | P = .30 | ||
| Blood draw prior to multiple myeloma diagnosis, y . | M-protein concentration* (g/dL) . | Involved FLC-ratio† . | Involved-uninvolved FLC concentration,† mg/dL . | Involved FLC concentration,† mg/dL . | ||
|---|---|---|---|---|---|---|
| n . | Median (range) . | n . | Median (range) . | Median (range) . | Median (range) . | |
| By year | ||||||
| 2 | 24 | 1.6 (0.4-3.7) | 23 | 12.1 (2.3-138.4) | 7.8 (0.6-61.9) | 8.5 (0.9-62.3) |
| 3 | 47 | 1.3 (0.5-3.1) | 46 | 10.7 (1.7-285.7) | 7.3 (0.6-118.2) | 8.3 (1.0-119.0) |
| 4 | 37 | 1.1 (0.5-3.9) | 30 | 11.3 (1.8-1428.0) | 5.1 (0.6-326.8) | 6.1 (0.9-327.0) |
| 5 | 26 | 1.2 (0.6-3.8) | 25 | 12.5 (1.7-4042.6) | 9.0 (0.6-322.9) | 9.2 (1.5-323.0) |
| 6 | 20 | 1.2 (0.6-3.6) | 19 | 14.3 (1.7-907.5) | 10.7 (0.6-205.8) | 11.1 (1.5-206.0) |
| 7 | 11 | 1.3 (0.7-3.5) | 11 | 32.6 (1.8-677.9) | 12.9 (0.9-180.7) | 14.0 (2.0-181.0) |
| 8 or more | 10 | 0.9 (0.5-1.8) | 8 | 19.4 (2.6-107.1) | 12.0 (1.8-32.7) | 13.0 (3.0-33.0) |
| Trend test | P = .025 | P = .35 | –‡ | P = .30 | ||
Individual sample results with an unquantifiable M-protein concentration were excluded from these analyses.
Subjects with a kappa-lambda FLC-ratio less than 0.26 and more than 1.65 were defined as having an “involved lambda” and “involved kappa” FLC, respectively. For persons with an involved lambda FLC, the involved FLC-ratio was computed as the ratio of lambda over kappa. For persons with an involved kappa FLC-ratio, it was computed by dividing kappa with lambda. Similarly, for persons with an involved lambda FLC, the involved-uninvolved FLC concentration was computed by subtracting kappa from lambda; and for persons with an involved kappa FLC, it was computed by subtracting lambda from kappa. All individuals with a kappa-lambda FLC-ratio within the normal range (reference: 0.26-1.65) were excluded from these analyses.
Because the involved-uninvolved FLC concentration (mg/dL) values were not normally distributed even after transformation, the estimated ptrend value (P = .27) was not considered to be reliable.