Comparison of serologic and molecular SARS-CoV 2 results in a large cohort in Southern Tuscany demonstrates a role for serologic testing to increase diagnostic sensitivity

Background

Since February 2020, Italian hospitals registered COVID-19 (COronaVIrus Disease 19) cases more often than the rest of the Europe. During this epidemic, health authorities requested swab tests, while seeking new patient paths.

Methods

A dual laboratory approach was evaluated, consisting of patient care reports for viral RNA detection on swabs and rapid serological tests in 516 patients (192 symptomatic or paucisymptomatic and 324 asymptomatic).

Results

We found the molecular positive fraction equal to 12% (23/192) among symptomatic/paucisymptomatic (S/P) and 15.4% (50/324) in asymptomatic (As) sets. Among subsets, we observed serologically positive results, corresponding to 35% (8/23) for S/P and 38% (19/50) for As. Among molecular negative cases, we detected specific Immunoglobulin G or M (Ig G or Ig M) positivity in the S/P cohort equal to 6.6% (11/167) and 6% (15/246) in As cases. For indeterminate molecular results, we found S/P serological positivity equal to 100% (1/1) and 54% (13/24) in As patients. We found higher (p < 0.05) seropositivity in older patients (n = 8) among symptomatic and positives for viral RNA (n.23).

Conclusions

It has been observed that a dual approach of serological and molecular tests detects a higher absolute number of disease cases in a pandemic context,which could improve monitoring and health surveillance efficacy. The age-related seropositivity frequency in this study, if confirmed, could enhance the validity of serological tests, especially in older patients.In these subjects, molecular positivity accompanied by serological positivity (distinct for M and G immunoglobulins) should help determine disease status and support decisions related to patient management.

Absent SEP during therapeutic hypothermia did not reappear after re-warming in comatose patients following cardiac arrest

BACKGROUND

Early prediction of neurological outcome for patients resuscitated from cardiac arrest (CA) is a challenging task. Therapeutic hypothermia (TH) has been shown to improve neurological outcome after CA. Two recent studies indicated that somatosensory evoked potentials (SEP) recorded during TH retains high prediction value for poor neurological outcome. It remains unclear whether TH can influence the recovery of bilaterally absent (BA) N20 after re-warming. The primary endpoint of the present study was to evaluate if patients with BA SEPs during TH can recover cortical responses after re-warming. The secondary endpoint was to evaluate whether BA SEPs recorded during TH retains its prediction value for poor neurological outcome as in normothermic patients.

METHODS

A single centre prospective cohort study including comatose adults resuscitated from in/out-of-hospital CA treated with TH. SEPs were recorded during TH (6-24 hours after CA) and after re-warming in those patients who remained comatose. Neurological outcome was assessed 6 months after CA using the Glasgow Outcome Scale.

RESULTS

Sixty patients were included. In patients with preserved SEP, no significant differences were found between N20 mean amplitude during TH and after re-warming. During TH, 24 patients showed bilaterally absent N20 but none of these recovered cortical responses after re-warming. All patients with absent SEPs during TH did not recover consciousness.

CONCLUSIONS

In a single centre cohort of comatose CA patients, our results showed that all patients with absent SEPs during early recording (6-24 hours) during TH showed bilaterally absent SEPs after re-warming. As a secondary result we confirmed previous data that BA SEPs during TH retains its prognostic value for poor neurological outcome, as in normothermic patients.