Table 2.
Characteristics of patients with a positive vs. negative cold agglutinin test.
| Parameter | CA test | |||
|---|---|---|---|---|
| Total (N = 35) | Negative (N = 19) | Positive (N = 16) | P value (positive vs. negative) | |
| Female sex | 23 (66) | 9 (47) | 14 (88) | 0.030* |
| Triggers | ||||
| Cold ambient air | 28 (80) | 12 (63) | 16 (100) | 0.009* |
| Immersion in <25°C water | 19 (54) | 7 (37) | 12 (75) | 0.041* |
| Higher summer humidity levels | 15 (43) | 4 (21) | 11 (69) | 0.007* |
| Ingestion of cold foods/drinks | 13 (37) | 4 (21) | 9 (56) | 0.043* |
| UCT score | 12 (7−14) | 13 (9−16) | 11 (7−12) | 0.023 ‡ |
| CST results | ||||
| Positive ice cube test | 21 (60) | 11 (58) | 10 (63) | 1.000 |
| Positive TempTest ® result | 12 (34) | 5 (26) | 7 (44) | 0.311 |
| CSTT (s) | 300 (30−300); N = 19 | 300 (98−300); N = 10 | 120 (30−300); N = 9 | 0.150 |
| CTT (°C) | 19 (15−25); N = 12 | 17 (16−25); N = 5 | 21 (14−24); N = 7 | 0.622 |
| Laboratory findings | ||||
| Erythrocyte count (1012/L) | 4.7 ± 0.4 | 4.9 ± 0.4 | 4.5 ± 0.3 | 0.005 † |
| Hemoglobin concentration (g/L) | 142.6 ± 10.4 | 148.4 ± 8.7 | 135.8 ± 7.8 | <0.001 † |
| Hematocrit level (%) | 41.7 ± 3.3 | 43.2 ± 3.4 | 40.0 ± 2.5 | 0.004 † |
| Thrombocyte count (109/L) | 265.9 ± 62.3 | 246.4 ± 52.3 | 289.0 ± 66.9 | 0.042 † |
| Monocyte count (109/L) | 0.5 ± 0.2 | 0.6 ± 0.2 | 0.4 ± 0.2 | 0.002 † |
| Leukocyte count (109/L) | 6.9 ± 1.7 | 7.3 ± 1.7 | 6.3 ± 1.5 | 0.070 |
| Neutrophil count (109/L) | 4.2 ± 1.3 | 4.5 ± 1.3 | 3.8 ± 1.2 | 0.121 |
| Lymphocyte count (109/L) | 1.9 ± 0.5 | 2.0 ± 0.5 | 1.9 ± 0.5 | 0.630 |
| Eosinophil count (109/L) | 0.2 ± 0.3 | 0.1 ± 0.1 | 0.1 ± 0.1 | 0.324 |
| Basophil count (109/L) | 0.04 ± 0.03; N = 34 | 0.04 ± 0.03; N = 19 | 0.04 ± 0.03; N = 15 | 0.620 |
| CRP (mg/L) | 1.7 (0.5−3.4) | 1.2 (0.5−3.2) | 2.1 (0.7−4.5) | 0.320 |
| Basal serum tryptase (ng/mL) | 5.5 (3.9−7.6); N = 34 | 6.1 (4.3−8.7); N = 18 | 5.3 (3.7−6.0) | 0.352 |
| Total IgE (IU/mL) | 99 (36−207); N = 31 | 82 (24−257); N = 15 | 113 (50−201) | 0.782 |
| Mean daily Temp. on the day when blood was drawn | 12.1 ± 7.3 | 9.3 ± 6.6 | 12.1 ± 7.3 | 0.008 † |
Data are given as no. (%), mean ± SD, and median (IQR). If data was not obtained in all patients, patient numbers are displayed as “N” next to results. Statistical significance of differences between patient groups was calculated by *Fisher’s Exact test, ‡Mann-Whitney U test, and †Independent-samples T test. Statistically significant P values are in bold. ColdU, cold urticaria; CA, cold agglutinin; CRP, C-reactive protein; CST, cold stimulation test; CSTT, critical stimulation time threshold; CTT, critical temperature threshold; IQR, interquartile range; N, number of patients; s, second; SD, standard deviation; UCT, Urticaria Control Test.