key: cord-0854974-eslf89dj
authors: Du, Li; Cao, Xiaoling; Chen, Jing; Wei, Xiuqi; Zeng, Yi; Cheng, Chen; Lin, Yuqi; Tan, Wenbin; Wang, Hui
title: Fecal occult blood and urinary cytology tests for rapid screening of inflammatory infection in the gastrointestinal and urological systems in patients with Coronavirus disease 2019
date: 2020-10-15
journal: J Clin Lab Anal
DOI: 10.1002/jcla.23626
sha: 05648590a1767587958c00eeabe94f226ea8265c
doc_id: 854974
cord_uid: eslf89dj

BACKGROUND: Gastrointestinal infections (GI) and urological infections (UI) have not been fully addressed in COVID‐19 patients. We aimed to evaluate the values of routine fecal occult blood (FOB) test and urinary cytology test (UCT) for screening of GI and UI in COVID‐19 patients. METHODS: In this retrospective study, COVID‐19 patients without associated comorbidities were divided into FOB‐ or UCT‐positive or FOB‐ or UCT‐negative groups. Their clinical characteristics and laboratory findings were then compared. RESULTS: A total of 13.6% of patients (47 of 345) tested positive for FOB, and 57.4% (27 of 47) of these patients lacked gastrointestinal symptoms. A total of 30.1% of patients (104 of 345) exhibited gastrointestinal symptoms, and 38.0% (131 of 345) were positive for either FOB or gastrointestinal symptoms. FOB‐positive patients possessed significantly higher levels of C‐reactive protein and fewer lymphocytes than FOB‐negative patients. A total of 36.9% of patients (80 of 217) exhibited positive UCT, and 97.5% (78 of 80) of these patients possessed normal levels of serum markers for renal injuries. Significant differences in age and sex ratios were observed between the UCT‐positive and UCT‐negative groups, and 72.4% (42 of 58) of female patients over 60 years old were UCT‐positive. CONCLUSIONS: Fecal occult blood test in combination with gastrointestinal symptoms could serve as a simple and useful screening approach for GI diagnoses for COVID‐19. Age and sex are risk factors for UI in COVID‐19 patients. UCT could be a sensitive tool for assessing early UI at a stage in which serum markers for renal injuries appear normal.

The coronavirus disease 2019 (COVID-19) pandemic has become a global threat to public health, where it has spread to 188 countries to cause infections in more than 26 522 000 people and has claimed 873 270 global victims to date (https://coron avirus.jhu.edu/ map.html). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative organism of COVID-19. The spike protein of SARS-CoV-2 is believed to mediate the entry of the virus into host cells via angiotensin-converting enzyme 2 (ACE2). 1 ACE2 has been found to be highly expressed in multiple tissues, including the lungs, heart, kidneys, testes, and intestines, 2, 3 suggesting that these organs are vulnerable to attack by SARS-CoV-2. Indeed, many patients with COVID-19 develop digestive symptoms, 4, 5 and viral nucleic acids have been identified in patient stool and urine specimens. 6, 7 Detection of SARS-CoV-2 is typically performed using nasopharyngeal swabs to determine viral load in the upper respiratory tract.

(UI) have been generally underestimated. Reports have shown that approximately 3%-26.0% of COVID-19 patients exhibit associated gastrointestinal symptoms. 4, 5, 8, 9 In this study, we speculated that simple and feasible tests could aid clinicians in quickly assessing the presence of GI and UI in COVID-19 patients. We found that 57.4% of patients (27 of 47) that tested positive for fecal occult blood (FOB), a test revealing the presence of GI, did not exhibit noticeable gastrointestinal symptoms. Furthermore, we found that 36.9% of patients (80/217) were positive for urinary cytology test (UCT); however, only 2.8% of patients (6/217) showed symptoms of UI (such as lumbago or urgent or frequent urination).

Our results suggest that both FOB and UCT, which are convenient, cheap, and rapid, can serve as valuable screening tools for the assessment of potential virus-induced GI and UI, particularly for patients in rural areas and underdeveloped countries where detection of viral nucleic acids or antibodies is not yet feasible. from the use of UCT for the assessment of UI. UCT included red blood cell (RBC) and white blood cell (WBC) analyses and routine urine analysis using a urine sample. We excluded patients with diabetes or hypertension to prevent the potential influence of secondary nephropathy. Figure 1 presents the application of the inclusion and exclusion criteria for patient enrollment. Based on FOB and UCT results, patients were divided into FOB-or UCT-positive or FOB-or UCT-negative groups, respectively. Clinical characteristics, specific symptoms, laboratory findings, and disease severity were compared between the groups.

Epidemiological data, clinical symptoms, comorbidities, and laboratory findings were obtained from electronic medical records. All data were reviewed by three experienced doctors.

Categorical variables were described according to frequency and percentage, and continuous variables were described as median values (interquartile range [IQR]). All statistical analyses were performed using the statistical software SPSS (version 23.0; IBM, Armonk, New York), and P < .05 was considered statistically significant. An independent-samples nonparametric test was used to analyze differences between the two groups. Binary logistic regression analysis was used to calculate odds ratios to assess risk factors associated with positive UCT according to gender. The data are presented as mean ± 95% confidence interval (CI). It has been reported that a decrease in lymphocytes (LY) and an elevation in the inflammatory marker C-reactive protein (CRP) are both more common in severe COVID-19 cases than they are in moderate cases or in healthy subjects. 11,12 COVID-19 patients also exhibited higher WBC levels. 11 Similarly, we found that there were Table 1 ). There was a significant increase in the proportion of FOB-positive cases as disease severity increased (mild, 11.7%; severe, 13.7%; and critical, 66.7%, P < .001, Table 1 (Table 1) . Additionally, we found that only 1.2% of patients (4 of 345) were positive according to the fecal white blood cell test (data not shown).

The study design is outlined in Table 2 The inflammatory marker CRP and the WBC were both higher (but not significantly higher) in UCT-positive patients than they were in UCT-negative patients ( Table 2) (Table S1 ).

In this study, we evaluated the benefits of using routine FOB and UCT to achieve a rapid assessment of GI and UI in COVID- 19 patients. 15 However, the gastrointestinal symptom rate in this study is slightly higher than the range of gastrointestinal symptoms (3%-26%) reported by other studies. 4, 5, 8, 9, 16 This variation may result from different criteria for diagnosing diarrhea among different hospitals 15 or from different physicians and/or sample sizes. This suggests that a more objective tool is needed to improve the diagnostic accuracy for GI. A FOB is a relatively objective laboratory test for the assessment of GI, although false-negative results have been a concern for physicians. 17, 18 In this study, 57.4% of FOB-positive patients did not In conclusion, our data provide insight into the benefits of FOB and UCT in regard to assessing GI and UI in COVID-19 patients.

These simple and cost-effective measures are of value for all COVID-19 patients, and they are particularly valuable for individuals in underdeveloped regions and countries where molecular diagnosis resources are lacking.

The manuscript has been approved by all of the authors for publication.

LD, XC, HW, and WT supervised and designed the study. LD, JC, XW, YZ, CC, YL, and HW performed the tests and collected the data.

XC, LD, and YZ performed the statistical analysis. LD, XC, JC, HW, and WT contributed to data interpretation. LD, HW, and WT prepared and revised the manuscript.

This study was approved by the Institutional Review Board (IRB) at the Union Hospital, and the requirement for a written consent form was waived by the IRB committee.

Yuqi Lin https://orcid.org/0000-0001-7401-1683

Hui Wang https://orcid.org/0000-0001-6549-6666 F I G U R E 2 UCT for assessment of UI in different ages and genders

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