ACEP COVID-19 Field Guide

Table of Contents

Laboratory Abnormalities


The clinical presentation and progression of patients suspected of having COVID-19 can range from mild to severe. Therefore, the laboratory workup for these patients is variable and depends significantly on the patient’s clinical presentation at the time of evaluation. 

In patients with severe illness, the following tests should be ordered: 

  • CBC; and
  • Comprehensive metabolic panel.

Additional tests to consider include:

  • ABG (as indicated to detect hypercarbia or acidosis);
  • Coagulation screen;
  • Inflammatory markers (serum procalcitonin and C-reactive protein);
  • Ferritin;
  • LDH;
  • CK, CK-MB;
  • Troponin;
  • Blood and sputum cultures; and/or

The most common laboratory abnormalities in patients hospitalized with pneumonia include leukopenia, lymphopenia, leukocytosis, elevated liver transaminases, elevated lactate dehydrogenase, and elevated C-reactive protein (Table 7.1). Laboratory abnormalities in severe disease are further described in Table 7.2.

Table 7.1 Laboratory findings at hospital admission.

Laboratory findings at hospital admission

Table 7.2 Laboratory abnormalities in severe disease.

Laboratory abnormalities in severe disease

Hypercoagulability and COVID-19

Some patients with COVID-19 may develop signs of a hypercoagulable state and be at increased risk for venous and arterial thrombosis of large and small vessels.4,5 Laboratory abnormalities commonly observed among hospitalized patients with COVID-19-associated coagulopathy include:

  • Mild thrombocytopenia;
  • Increased D-dimer levels;
  • Increased fibrin degradation products; and/or
  • Prolonged prothrombin time.

Elevated D-dimer levels have been strongly associated with greater risk of death.4, 6-8

There are several reports of hospitalized patients with thrombotic complications, most frequently deep venous thrombosis and pulmonary embolism.9-11 Other reported manifestations include:

  • Microvascular thrombosis of the toes;
  • Clotting of catheters;
  • Myocardial injury with ST-segment elevation; and/or
  • Large vessel strokes.12-15

The pathogenesis for COVID-19-associated hypercoagulability remains unknown. However, hypoxia and systemic inflammation secondary to COVID-19 may lead to high levels of inflammatory cytokines16 and activation of the coagulation pathway. There are limited data available to inform clinical management around prophylaxis or treatment of venous thromboembolism in COVID-19 patients.

More information on hypercoagulability and COVID-19 is available from the American Society of Hematology and NIH: Coronavirus Disease 2019 (COVID-19) Treatment Guidelines – Antithrombotic Therapy in Patients with COVID-19.



  1. Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China [published correction appears in Lancet. 2020 Jan 30]. Lancet. 2020;395(10223):497-506. doi:10.1016/S0140-6736(20)30183-5
  2. Chen N, Zhou M, Dong X, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet. 2020;395(10223):507-513. doi:10.1016/S0140-6736(20)30211-7
  3. Wang D, Hu B, Hu C, et al. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China [published online ahead of print, 2020 Feb 7]. JAMA. 2020;e201585. doi:10.1001/jama.2020.1585
  4. Bikdeli B, Madhavan M, Jimenez D, et al. COVID-19 and Thrombotic or Thromboembolic Disease: Implications for Prevention, Antithrombotic Therapy, and Follow-up. JACC. April 2020, S0735-1097(20)35008-7. doi: 10.1016/j.jacc.2020.04.031 
  5. Cannegieter, S; Klok, FA. COVID-19 associated coagulopathy and thromboembolic disease: Commentary  on an interim expert guidance. Research and Practice in Thrombosis and Haemostasis, April 2020.   doi:10.1002/rth2.12350
  6. Lippi G, Plebani M, Henry MB. Thrombocytopenia is associated with severe coronavirus disease 2019 (COVID-19) infections: A meta-analysis. Clinica Chimica Acta. 2020 Mar 13;506:145-148. doi:10.1016/j.cca.2020.03.022 
  7. Lippi G, Favaloro EJ. D-dimer is associated with severity of coronavirus disease 2019 (COVID-19): a pooled analysis. Thrombosis and Haemostasis [in press].  doi: 10.1055/s-0040-1709650
  8. Tang N, Li D, Wang X, et al. Abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia. J Thromb Haemost. Feb 2020.  doi: 10.1111/jth.14768
  9. American Venous Forum. Considerations in prophylaxis and treatment of VTE in COVID-19 Patients. 2020. Accessed April 2020. 
  10. Klok FA, Kruip MJHA, van der Meer NJM, et al. Incidence of thrombotic complications in critically ill ICU patients with COVID-19. Thrombosis Research, April 2020 [in press]. doi: 10.1016/j.thromres.2020.04.013 
  11. Helms J, Tacquard C, Severac F, et al. High risk of thrombosis in patients in severe SARS-CoV-2 infection: a multicenter prospective cohort study. Intensive Care Medicine, April 2020 [in press]. doi: 10.1007/s00134-020-06062-x
  12. Grillet F, Behr J, Calame H, et al. Acute Pulmonary Embolism Associated with COVID-19 Pneumonia Detected by Pulmonary CT Angiography. Radiology. Published online Apr 23 2020. doi: 10.1148/radiol.2020201544
  13. Oxley T, Mocco J, Majidi S, et al. Large-Vessel Stroke as a Presenting Feature of Covid-19 in the Young. NEJM. April 2020. doi: 10.1056/NEJMc2009787
  14. Avula A, Nalleballe K, Narula N, et al. COVID-19 presenting as stroke [published online ahead of print, 2020 Apr 28]. Brain Behav Immun. 2020;S0889-1591(20)30685-1. doi:10.1016/j.bbi.2020.04.077
  15. Margo C, Mulvey J, Berlin D, et al. Complement associated microvascular injury and thrombosis in the pathogenesis of severe COVID-19 infection: A report of five cases. Translational Research. April 2020 S1931-5244(20)30070-0. doi: 10.1016/j.trsl.2020.04.007
  16. Bangalore, S; Sharma, A; Slotwiner, A et al. ST-Segment Elevation in Patients with COVID-19-A Case Series. NEJM. April 17, 2020. doi: 10.1056/NEJMc2009020



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