A Comparative Study of Levin Vs Z Stroke Wound Swab Techniques in Diagnosing Infection in Patients With Chronic Wounds Using Wound Biopsy as Gold Standard at the Kenyatta National Hospital.

Abstract

Background: Chronic wounds reduce quality of life and increase societal socioeconomic burden by increasing cost of healthcare, reducing productivity with loss of man hours. Wound infection being a factor that leads to chronicity should be diagnosed early and managed accordingly to facilitate timely wound healing. There are a number of ways that have been devised to diagnose wound infection, with standard being wound biopsy, which is costly and painful. This study seeks to determine the wound swab technique that gives better micro-organism yield in diagnosing chronic wound infection. Study Design: This was a comparative cross-sectional study. Objective: The aim of the study was to compare effectiveness of Levin and Z stroke wound swab techniques in diagnosis of infection among patient with chronic wounds at KNH. Methods:145 patients above 18 years with wounds of duration more than 4 weeks without healing and gave informed written consent were consecutively enrolled into the study at the KNH medical and surgical wards, surgical outpatient clinics and theatres. Data collected including demographics, etiology, signs of wound infection and duration of wounds were documented. Subsequently 2 swabs Levin and z-stroke plus punch biopsy of wounds were taken from each patient with specimen submitted to lab within 1hr of collection. Culture of the specimen was done and data from the laboratory was analyzed using SPSS version 21. Results: Ninety males and fifty five females were recruited into the study. The infection rate was 50%, mean age was 37years, the youngest patient was 18 years while the oldest was 79 years. Surgical site infection was the commonest cause of chronic wounds at 31.7% while chronic osteomyelitis was least at 1.4%.The commonest isolated organism was staphylococcus aureus at 18.6% with beta hemolytic streptococcus the least at 1.4%.Most of the wounds were located in the lower limbs at 38%. The sensitivity and specificity of Levin technique were 95.8% & 61.6% respectively and diagnostic accuracy of 78.6%. Z-stroke had sensitivity of 97.2% & specificity of61.6% with diagnostic accuracy of 79.3%. Both Levin and Z-stroke are equally effective at picking infection in chronic wounds. Conclusion: Both Levin and Z-stroke are equally effective at picking infection in patients with chronic at Kenyatta National Hospital. This is in contrast to studies in other settings which depict that Levin wound swab technique to have a better pick rate than z-stroke.