Diagnostic Testing Procedures and Challenges for Primary Immunodeficiencies.

Primary immunodeficiencies are rare but are often on the differential diagnosis list when patients present with recurrent or atypical infections. Patients with primary immunodeficiencies can present with a variety of symptoms and can present providers with diagnostic challenges given this variability, and the severe implications of immunodeficiencies can sometimes lead providers to pursue broad workups that may not be necessary. However, there are certain symptom patterns providers can look out for and diagnostic steps that can be taken to triage these presentations. We have used the practice modeled in the "Five Fingers of the Immune Workup" to outline common laboratory tests for clinicians to order when they are concerned for immunodeficiencies while remembering that these diagnoses are often rare, and true concern for this pathology would warrant referral to a specialist. [Pediatr Ann. 2022;51(12):e480-e484.].

Clinical characteristics of hospitalized patients with false-negative severe acute respiratory coronavirus virus 2 (SARS-CoV-2) test results.

OBJECTIVE: To determine clinical characteristics associated with false-negative severe acute respiratory coronavirus virus 2 (SARS-CoV-2) test results to help inform coronavirus disease 2019 (COVID-19) testing practices in the inpatient setting. DESIGN: A retrospective observational cohort study. SETTING: Tertiary-care facility. PATIENTS: All patients 2 years of age and older tested for SARS-CoV-2 between March 14, 2020, and April 30, 2020, who had at least 2 SARS-CoV-2 reverse-transcriptase polymerase chain reaction tests within 7 days. METHODS: The primary outcome measure was a false-negative testing episode, which we defined as an initial negative test followed by a positive test within the subsequent 7 days. Data collected included symptoms, demographics, comorbidities, vital signs, labs, and imaging studies. Logistic regression was used to model associations between clinical variables and false-negative SARS-CoV-2 test results. RESULTS: Of the 1,009 SARS-CoV-2 test results included in the analysis, 4.0% were false-negative results. In multivariable regression analysis, compared with true-negative test results, false-negative test results were associated with anosmia or ageusia (adjusted odds ratio [aOR], 8.4; 95% confidence interval [CI], 1.4-50.5; P = .02), having had a COVID-19-positive contact (aOR, 10.5; 95% CI, 4.3-25.4; P < .0001), and having an elevated lactate dehydrogenase level (aOR, 3.3; 95% CI, 1.2-9.3; P = .03). Demographics, symptom duration, other laboratory values, and abnormal chest imaging were not significantly associated with false-negative test results in our multivariable analysis. CONCLUSIONS: Clinical features can help predict which patients are more likely to have false-negative SARS-CoV-2 test results.