Table 1

Findings and lab results

Variable	Reference range (units)	Value
Vital signs
Heart rate	60–100 bpm	140 bpm
Blood pressure	90/60-130/90 mm Hg	135/69 mm Hg
Respiratory rate	12–18 breaths/min	27 breaths/min
Oxygen saturation	>92% on room air	97% on room air
Temperature	36°C–37.5°C	37 °C
Investigations
Haemoglobin	125–170 g/L	Baseline 140 g/L 80 g/L initial 56 g/L after rapid haemolysis within 12 hours
Mean corpuscular volume (MCV)	80–98 fL	123 fL
Reticulocyte count	30–110×10⁹/L	99×10⁹/L initial 329×10⁹/L after rapid haemolysis within 24 hours
Blood film		Significant for red cell agglutination which dispersed when heated to 37°C, nucleated red cells, polychromasia and spherocytes (figure 1)
Platelets	150–400×10⁹/L	229×10⁹/L
Coagulation factors	International Normalized Ratio (INR) 0.9–1.1 Prothrombin time (PT) 9.4–12.4 s Partial Thromboplastin Time (PTT) 21–29 s	INR 1.1 PT 11.1 s PTT 17 s
Liver enzymes	Aspartate aminotransferase (AST) 15–37 IU/L Alanine aminotransferase (ALT) 17–63 IU/L Alkaline phosphatase (ALP) 50–136 IU/L	AST 203 IU/L initial; repeat 47 IU/L ALT 33 IU/L ALP 169 IU/L initial; repeat 107 IU/L
Serum albumin	34–50 g/L	33 g/L
Bilirubin	Total 2–20 µmol/L Direct <5 µmol/L	Total 66 µmol/L Direct 9 µmol/L
Lactate dehydrogenase (LDH)	50–150 U/L	2362 U/L At discharge: 430 U/L (near baseline)
Haptoglobin	0.3–2.0 g/L	<0.08 g/L
D-Dimer	<0.5 ng/mL	>4400 ng/mL
IgM level	0.45–2.81 g/L	Preplasma exchange: 18.9 g/L Postplasma exchange: 2.67 g/L
Direct antiglobulin test		Positive; C3d 1+
Thermal amplitude		34°C
Cold agglutination titre		1:256 at 30°C 1:1024 at 22°C
Bacterial blood culture x2	Incubated for 5 days	No growth
Urine culture		No growth
COVID-19 PCR from Nasopharyngeal swab		Detected (2 March 2021)
COVID-19 variants of concern Gene mutation, NAA+probe		Not detected
Imaging
Thorax CT scan with pulmonary angiogram contrast		No evidence of pulmonary embolism. Diffuse patchy peripherally predominant bilateral ground glass opacities in keeping with known COVID-19 infection/pneumonia.
Echocardiogram		Normal left ventricular size, borderline concentric left ventricular hypertrophy (LVH), ejection fraction of 60%. No obvious regional wall motion abnormalities. Normal right ventricular (RV) size with borderline RV dysfunction.