Table 1: Laboratory parameters. Centers for Disease Control and Prevention diagnostic criteria of Multisystem Inflammatory Syndrome in Children (abnormal findings are bold lettered) [11].

Laboratory parameters

Reference range

In the emergency department

At PICU admission

Haemoglobin (g/dL)

12 - 15

12.4

10.9

Platelet count (per μL)

120000 - 400000

270000

193000

White-cell count (per μL)

5000 - 14500

12000

6500

Lymphocyte count (per μL)

2500 - 8500

400

200

Neutrophil count (per μL)

1800 - 7700

10500

5700

C-reactive protein (mg/L)

1 - 5

147

224.5

Procalcitonin (ng/mL)

<0.5

-

1.09

Prothrombin activity %

70 - 150

56

54

International normalized ratio

0.6 - 1.3

1.5

1.5

Fibrinogen (mg/dL)

150 - 600

945

708

D-Dimer (ng/mL)

0.0 - 500

-

7084

Interleukin-6 (pg/mL)

150 - 600

-

734.9

Ferritin (ng/mL)

15 - 150

-

188

N-terminal B-type natriuretic peptide (pg/mL)

Patients with acute dyspnea N-terminal B-type natriuretic peptide:

Heart failure unlikely < 300

Heart failure very likely

< 50 years > 450

50-75 years > 900

- > 75 years > 1800

-

1353

Troponin I (ng/mL)

0.000 - 0.120

-

<0.012

Centers for Disease Control and Prevention. Case Definition for Multisystem Inflammatory Syndrome in Children (diagnostic criteria are bold lettered) [8].

An individual aged <21 years presenting fever (>38.0°C for ≥24 hours, or report of subjective fever lasting ≥24 hours), laboratory evidence of inflammation (including, but not limited to, one or more of the following: an elevated C-reactive protein, erythrocyte sedimentation rate, fibrinogen, procalcitonin, D-Dimer, ferritin, lactic acid dehydrogenase, or Interleukin-6, elevated neutrophils, reduced lymphocytes and low albumin), and evidence of clinically severe illness requiring hospitalization, with multisystem (>2) organ involvement (cardiac, renal, respiratory, hematologic, gastrointestinal, dermatologic or neurologic); and

No alternative plausible diagnoses; and

Positive for current or recent SARS-CoV-2 infection by real-time polymerase chain reaction, serology, or antigen test; or COVID-19 exposure within the 4 weeks prior to the onset of symptoms.