Examining the utility of extended laboratory panel testing in the emergency department for risk stratification of patients with COVID-19: a single-centre retrospective service evaluation

  1. Mark J Ponsford
  2. Ross J Burton
  3. Leitchan Smith
  4. Palwasha Y Khan
  5. Robert Andrews
  6. Simone Cuff
  7. Laura Tan
  8. Matthias Eberl
  9. Ian R Humphreys
  10. Farbod Babolhavaeji
  11. Andreas Artemiou
  12. Manish Pandey
  13. Stephen R A Jolles
  14. Jonathan Underwood

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Abstract

The role of specific blood tests to predict poor prognosis in patients admitted with infection from SARS-CoV-2 remains uncertain. During the first wave of the global pandemic, an extended laboratory testing panel was integrated into the local pathway to guide triage and healthcare resource utilisation for emergency admissions. We conducted a retrospective service evaluation to determine the utility of extended tests (D-dimer, ferritin, high-sensitivity troponin I, lactate dehydrogenase and procalcitonin) compared with the core panel (full blood count, urea and electrolytes, liver function tests and C reactive protein).

Methods

Clinical outcomes for adult patients with laboratory-confirmed COVID-19 admitted between 17 March and 30 June 2020 were extracted, alongside costs estimates for individual tests. Prognostic performance was assessed using multivariable logistic regression analysis with 28-day mortality used as the primary endpoint and a composite of 28-day intensive care escalation or mortality for secondary analysis.

Results

From 13 500 emergency attendances, we identified 391 unique adults admitted with COVID-19. Of these, 113 died (29%) and 151 (39%) reached the composite endpoint. ‘Core’ test variables adjusted for age, gender and index of deprivation had a prognostic area under the curve of 0.79 (95% CI 0.67 to 0.91) for mortality and 0.70 (95% CI 0.56 to 0.84) for the composite endpoint. Addition of ‘extended’ test components did not improve on this.

Conclusion

Our findings suggest use of the extended laboratory testing panel to risk stratify community-acquired COVID-19 positive patients on admission adds limited prognostic value. We suggest laboratory requesting should be targeted to patients with specific clinical indications.

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  1. ScreenIT

    SciScore for 10.1101/2020.10.06.20205369: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Cost estimates were obtained from the Health Board Laboratory Medicine Directorate, reflecting consumables, reagent, analyser running and maintenance costs, and staff time chargeable to NHS test requestors.
    Cost
    suggested: (COST, RRID:SCR_014098)
    Multivariate logistic regression was implemented in Python (version 3.7) using the Scikit-Learn package (version 0.23) (21) and Statsmodels (version 0.11).
    Python
    suggested: (IPython, RRID:SCR_001658)
    Scikit-Learn
    suggested: (scikit-learn, RRID:SCR_002577)

    Results from OddPub: Thank you for sharing your data.

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Our evaluation also has a number of limitations, reflecting the challenges of clinical data collection during an epidemic. It represents retrospective experience from a single tertiary referral centre, limiting sample size and the generalisability of our findings. Secondly, availability of extended test panel results during the early admission period was mixed. Admission D-dimer and hs-Trop results were available for 70-80% of patients, comparing favourably to a similar UK registry-based study where D-dimer results were only available at time of admission in 37.2% (17). Conversely, we observed high rates of missing data for LDH, ferritin, and PCT, undermining their relevance as a prognostic tool. This was likely due to operational factors such as a delay in test roll out relative to epidemic peak, and requirement for an additional sample tube. Because it cannot be assumed that data are missing at random, we chose to perform complete case analysis. Although this limits our statistical power, it avoids unfounded assumptions and potentially invalid imputation. In its current form, the CHAD-registry lacks detailed information on patient-level physiological observations, nature of co-morbidities, and therapeutic interventions. Similarly, all registry-linked laboratory values were available to clinicians, and are likely to have influenced management decisions. With advances in clinical care diagnostics, therapeutics are likely to alter the observed performance of the prognostic mod...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  2. Version published to 10.1136/jclinpath-2020-207157
  3. Version published to 10.1101/2020.10.06.20205369v2 on medRxiv
  4. Version published to 10.1101/2020.10.06.20205369v1 on medRxiv