CMAAO Coronavirus Facts and Myth Buster 103: Lab Parameters |
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CMAAO Coronavirus Facts and Myth Buster 103: Lab Parameters

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(With inputs from Dr Monica Vasudev)

889 What are the common lab findings

Lymphopenia is the most common laboratory finding seen in 83% of hospitalized patients. Worsening lymphopenia is a bad sign.

Procalcitonin is usually normal on admission, but the levels may increase among those admitted to the intensive care unit (ICU).

Findings associated with more illness severity: Lymphopenia, Neutrophilia, Elevated levels of serum alanine aminotransferase and aspartate aminotransferase, Elevated lactate dehydrogenase, High C-reactive protein (CRP) level and High ferritin levels.

Elevated D-dimer (>1 mcg/mL), elevated prothrombin time (PT), elevated troponin, elevated CPK, acute kidney injury are linked to mortality.

Elevated D-dimer and lymphopenia have been tied to mortality.

Progressive decline in the lymphocyte count and rise in the D-dimer over time have been noted in nonsurvivors compared with more stable levels in survivors.

Markers of inflammation or coagulation (D-dimer level >1 mcg/mL on admission, elevated fibrin degradation products, prolonged activated partial thromboplastin and prothrombin times) are linked to death.

890:  IL-6 and D-dimer

Cohort drawn from two NewYork-Presbyterian hospitals: Estimation of inflammation through interleukin-6 (IL-6) concentrations and thrombosis through D-dimer concentrations revealed a 10% increased risk for death with every 10% increase of IL-6 (adjusted hazard ratio [aHR], 1.11; 95% confidence interval [CI], 1.02–1.20) or D-dimer concentration (aHR, 1.10; 95% CI, 1.01–1.19).

891: D-dimer cut off

D-dimer = 2.0 ug/ml (four-fold increase) on admission might be the optimum cutoff to predict in-hospital mortality.

[Zhenlu Zhang Laboratory Medicine, Wuhan Asia Heart Hospital. No.753 Jinghan Avenue, Wuhan, China, 430022].

892: Coagulation testing

  • Prothrombin time (PT) and aPTT normal or slightly prolonged
  • Platelet counts normal or increased (mean, 348,000/microL)
  • Fibrinogen elevated (mean, 680 mg/dL; range 234 to 1344)
  • D-dimer elevated (mean, 4877 ng/mL; range, 1197 to 16,954)

Other assays

  • Factor VIII activity increased (mean, 297 units/dL)
  • VWF antigen elevated considerably (mean, 529; range 210 to 863), consistent with endothelial injury or perturbation
  • Minor changes in natural anticoagulants
    • Small reduction in antithrombin and free protein S
    • Small rise in protein C

TEG findings

  • Reaction time (R) decreased, consistent with increased early thrombin burst, in 50% of patients
  • Clot formation time (K) reduced, in line with increased fibrin generation, in 83%
  • Maximum amplitude (MA) increased, consistent with greater clot strength, in 83%
  • Clot lysis at 30 minutes (LY30) reduced, in line with reduced fibrinolysis, in 100%.

893: Laboratory features linked with severe COVID-191-6


Probable threshold

Increase in:


>1000 ng/mL (normal range: <500 ng/mL)


>100 mg/L (normal range: <8.0 mg/L)


>245 units/L (normal range: 110 to 210 units/L)


>2× the upper limit of normal (normal range for troponin T high sensitivity: females 0 to 9 ng/L; males 0 to 14 ng/L)


>500 mcg/L (normal range: females 10 to 200 mcg/L; males 30 to 300 mcg/L)


>2× the upper limit of normal (normal range: 40 to 150 units/L)

Decrease in:

  Absolute lymphocyte count

<800/microL (normal range for age ≥21 years: 1800 to 7700/microL)

These laboratory features are linked with severe disease in patients with COVID-19; however, they have not been shown to have a prognostic value. These thresholds are used to identify patients at risk for severe disease; they are deduced from published cohort data and individualized to the reference values used at particular laboratory. The specific thresholds are not well known and may not be applicable if laboratories use other reference values.

COVID-19: coronavirus disease 2019; CRP: C-reactive protein; LDH: lactate dehydrogenase; CPK: creatine phosphokinase.


  1. Guan WY, Ni ZY, Hu Y, et al. Clinical characteristics of coronavirus disease 2019 in China. N Engl J Med 2020.
  2. Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet 2020; 395:497.
  3. Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet 2020; 395:1054.
  4. Wang D, Hu B, Hu C, et al. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China. JAMA 2020.
  5. Wu Z, McGoogan JM. Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: Summary of a report of 72,314 cases from the Chinese Center for Disease Control and Prevention. JAMA 2020.
  6. Ruan Q, Yang K, Wang W, et al. Clinical predictors of mortality due to COVID-19 based on an analysis of data of 150 patients from Wuhan, China. Intensive Care Med 2020.

(Source: UPTODATE)


Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA

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