Table 1.
Descriptive statistics of the development data set and laboratory concentrations
| Pre-COVID-19 n=5890 |
Untested n=3303 |
PCR negative n=945 |
PCR positive n=279 |
|
| Age in years* | 61 (21) | 60 (21) | 66 (18) | 69 (15) |
| Female gender, n (%) | 2909 (49.4) | 1659 (50.2) | 466 (49.3) | 95 (34.1) |
| Specialism, n (%) | ||||
| Internal medicine | 1648 (28.0) | 896 (27.1) | 244 (25.8) | 71 (25.4) |
| Surgery | 1007 (17.1) | 679 (20.6) | 51 (5.4) | 5 (1.8) |
| Neurology | 775 (13.2) | 468 (14.2) | 64 (6.8) | 5 (1.8) |
| Pulmonary medicine | 714 (12.1) | 220 (6.7) | 326 (34.5) | 167 (59.9) |
| Cardiology | 560 (9.5) | 322 (9.7) | 145 (15.3) | 6 (2.2) |
| Urology | 309 (5.2) | 148 (4.5) | 15 (1.6) | 7 (2.5) |
| Gastroenterology | 306 (5.2) | 224 (6.8) | 27 (2.9) | 1 (0.4) |
| Geriatrics | 189 (3.2) | 95 (2.9) | 52 (5.5) | 15 (5.4) |
| Orthopaedics | 147 (2.5) | 109 (3.3) | 11 (1.2) | 0 (0.0) |
| Gynaecology | 118 (2.0) | 82 (2.5) | 2 (0.2) | 0 (0.0) |
| Other | 117 (2.0) | 60 (1.8) | 8 (0.8) | 2 (0.7) |
| Haemoglobin* (g/L) | 13.2 (2.1) | 13.3 (2.0) | 13.3 (2.2) | 13.8 (1.8)‡ |
| Haematocrit* (L/L) | 0.403 (0.059) | 0.405 (0.056) | 0.405 (0.062) | 0.417 (0.047)‡ |
| Erythrocytes* (/pL) | 4.41 (0.69) | 4.43 (0.66) | 4.41 (0.72) | 4.61 (0.60)‡ |
| MCV* (fL) | 91.8 (6.4) | 91.9 (6.1) | 92.4 (6.7) | 90.7 (5.5) |
| MCH* (mmol) | 1.859 (0.157) | 1.876 (0.150) | 1.874 (0.172) | 1.869 (0.141) |
| MCHC* (mmol/L) | 20.2 (0.9) | 20.4 (0.9) | 20.3 (1.0) | 20.6 (0.8)‡ |
| Thrombocytes* (/nL) | 263 (99) | 266 (100) | 269 (105) | 217 (123)‡ |
| Leucocytes† (/nL) | 9.30 (7.06–12.16) | 8.92 (7.01–11.89) | 9.66 (7.17–12.94) | 6.33 (4.74–8.48)‡ |
| Neutrophils† (/nL) | 6.62 (4.51–9.53) | 6.10 (4.42–8.94) | 7.01 (4.79–10.02) | 4.71 (3.30–6.94)‡ |
| Eosinophils† (/nL) | 0.09 (0.03–0.17) | 0.09 (0.03–0.18) | 0.08 (0.02–0.17) | 0.00 (0.00–0.02)‡ |
| Basophils† (/nL) | 0.04 (0.02–0.05) | 0.04 (0.02–0.05) | 0.04 (0.02–0.05) | 0.01 (0.01–0.02)‡ |
| Lymphocytes† (/nL) | 1.47 (0.93–2.13) | 1.56 (1.05–2.18) | 1.31 (0.80–2.03) | 0.86 (0.59–1.21)‡ |
| Monocytes† (/nL) | 0.70 (0.52–0.93) | 0.69 (0.52–0.91) | 0.74 (0.54–1.01) | 0.45 (0.32–0.64)‡ |
| Glucose† (mmol/L) | 6.76 (5.83–8.39) | 6.68 (5.76–8.14) | 6.98 (5.95–8.85) | 6.77 (5.98–8.48)‡ |
| Bilirubin† (μmol/L) | 7.5 (5.0–11.6) | 7.4 (5.1–10.9) | 8.3 (5.6–12.4) | 8.2 (6.3–11.4) |
| ASAT† (U/L) | 24.0 (19.1–32.2) | 26.5 (21.6–35.1) | 27.7 (21.7–39.2) | 40.7 (30.2–57.2)‡ |
| ALAT† (U/L) | 24.3 (17.8–35.3) | 25.3 (18.4–36.2) | 25.7 (18.4–40.0) | 33.7 (23.3–50.0)‡ |
| LD† (U/L) | 201 (173–240) | 198 (170–236) | 215 (178–263) | 300 (238–403)‡ |
| CK† (U/L) | 82 (51–134) | 83 (52–136) | 76 (51–125) | 124 (62–222)‡ |
| ALP† (IU/L) | 83.0 (68.0–105.0) | 81.0 (65.8–102.5) | 86.9 (67.9–110.0) | 71.0 (58.8–85.0)‡ |
| gGT† (U/L) | 27.0 (17.0–53.0) | 28.4 (18.4–50.5) | 37.0 (22.4–68.9)‡ | 42.0 (28.0–83.5)‡ |
| BUN† (mmol/L) | 5.7 (4.3–8.0) | 5.8 (4.3–7.8) | 6.2 (4.6–9.4) | 6.1 (4.7–8.9) |
| CKD-epi† (mL/min/m2) | 80.9 (58.0–99.1) | 85.0 (63.5–103.3) | 79.1 (52.1–96.6) | 76.6 (54.9–91.2) |
| Potassium* (mmol/L) | 4.06 (0.50) | 4.03 (0.49) | 4.07 (0.55) | 3.91 (0.47) |
| Sodium* (mmol/L) | 139.2 (4.0) | 138.5 (3.9) | 138.0 (4.3)‡ | 136.4 (4.1)‡ |
| Chloride* (mmol/L) | 104.4 (4.6) | 103.8 (4.5) | 102.9 (4.8) | 101.6 (4.4)‡ |
| Albumin* (g/L) | 42.4 (4.9) | 42.3 (4.5) | 40.8 (4.8) | 38.4 (3.8)‡ |
| CRP† (mg/L) | 8 (2–41) | 5 (1–30) | 18 (3–69)‡ | 77 (37–136)‡ |
Shown are the laboratory tests routinely requested at ED presentations and their mean/median results (in the development data set) for presentations before the first patient with COVID-19 in the Netherlands (‘Pre-COVID-19’), presentations thereafter that were not tested for COVID-19 (‘Untested’), tested negative (‘PCR negative’) and tested positive (‘PCR positive’).
*Results with normal distribution, where the mean value and SD are shown.
†Results with skewed or heavy tailed distribution, where the median value and IQR are shown.
‡Clinically relevant difference from the pre-COVID-19 category (based on the total allowable error).
ALAT, alanine aminotransferase; ALP, alkaline phosphatase; ASAT, aspartate aminotransferase; BUN, blood urea nitrogen; CK, creatine kinase; CKD-epi, Chronic Kidney Disease Epidemiology Collaboration; CRP, C reactive protein; ED, emergency department; gGT, gamma-glutamyltransferase; LD, lactate dehydrogenase; MCH, mean cellular haemoglobin; MCHC, mean cellular haemoglobin concentration; MCV, mean corpuscular volume.