{"id":844257,"date":"2022-02-05T19:04:05","date_gmt":"2022-02-06T00:04:05","guid":{"rendered":"https:\/\/myendoconsult.com\/learn\/?p=844257"},"modified":"2023-03-16T05:50:43","modified_gmt":"2023-03-16T10:50:43","slug":"fena-calculator","status":"publish","type":"post","link":"https:\/\/myendoconsult.com\/learn\/fena-calculator\/","title":{"rendered":"Fractional Excretion of Sodium (FENa) Calculator"},"content":{"rendered":"<p>The <strong>Fractional Excretion of Sodium<\/strong> Calculation (FENa) requires the following patient parameters : <strong>Plasma Sodium<\/strong> and <strong>Urine Sodium<\/strong> in mEq\/L. <strong>Plasma Creatinine<\/strong> and <strong>Urine Creatinine<\/strong> in mg\/dL.<\/p>\n<div class='fluentform ff-default fluentform_wrapper_16 ffs_default_wrap'><form data-form_id=\"16\" id=\"fluentform_16\" class=\"frm-fluent-form fluent_form_16 ff-el-form-top ff_form_instance_16_1 ff-form-loading ff_calc_form ffs_default\" data-form_instance=\"ff_form_instance_16_1\" method=\"POST\" ><fieldset  style=\"border: none!important;margin: 0!important;padding: 0!important;background-color: transparent!important;box-shadow: none!important;outline: none!important; min-inline-size: 100%;\">\n                    <legend class=\"ff_screen_reader_title\" style=\"display: block; margin: 0!important;padding: 0!important;height: 0!important;text-indent: -999999px;width: 0!important;overflow:hidden;\">FeNA calculator (#16)<\/legend>        <div\n                style=\"display: none!important; position: absolute!important; transform: translateX(1000%)!important;\"\n                class=\"ff-el-group ff-hpsf-container\"\n        >\n            <div class=\"ff-el-input--label asterisk-right\">\n                <label for=\"ff_16_item_sf\" aria-label=\"Updates\">\n                    Updates                <\/label>\n            <\/div>\n            <div class=\"ff-el-input--content\">\n                <input type=\"text\"\n                       name=\"item_16__fluent_sf\"\n                       class=\"ff-el-form-control\"\n                       id=\"ff_16_item_sf\"\n                \/>\n            <\/div>\n        <\/div>\n        <input type='hidden' name='__fluent_form_embded_post_id' value='844257' \/><input type=\"hidden\" id=\"_fluentform_16_fluentformnonce\" name=\"_fluentform_16_fluentformnonce\" value=\"252c101e15\" \/><input type=\"hidden\" name=\"_wp_http_referer\" value=\"\/learn\/wp-json\/wp\/v2\/posts\/844257\" \/><div class='ff-el-group'><div class=\"ff-el-input--label ff-el-is-required asterisk-right\"><label for='ff_16_serum_sodium' id='label_ff_16_serum_sodium' aria-label=\"Plasma Sodium\">Plasma Sodium<\/label><\/div><div class='ff-el-input--content'><input type=\"number\" name=\"serum_sodium\" id=\"ff_16_serum_sodium\" class=\"ff-el-form-control\" placeholder=\"value in mEq\/L\" data-name=\"serum_sodium\" inputmode=\"numeric\" step=\"any\"  aria-invalid=\"false\" aria-required=true><\/div><\/div><div class='ff-el-group'><div class=\"ff-el-input--label ff-el-is-required asterisk-right\"><label for='ff_16_serum_creatinine' id='label_ff_16_serum_creatinine' aria-label=\"Plasma Creatinine\">Plasma Creatinine<\/label><\/div><div class='ff-el-input--content'><input type=\"number\" name=\"serum_creatinine\" id=\"ff_16_serum_creatinine\" class=\"ff-el-form-control\" placeholder=\"value in mg\/dL\" data-name=\"serum_creatinine\" inputmode=\"numeric\" step=\"any\"  aria-invalid=\"false\" aria-required=true><\/div><\/div><div class='ff-el-group'><div class=\"ff-el-input--label ff-el-is-required asterisk-right\"><label for='ff_16_urine_sodium' id='label_ff_16_urine_sodium' aria-label=\"Urine Sodium\">Urine Sodium<\/label><\/div><div class='ff-el-input--content'><input type=\"number\" name=\"urine_sodium\" id=\"ff_16_urine_sodium\" class=\"ff-el-form-control\" placeholder=\"value in mEq\/L\" data-name=\"urine_sodium\" inputmode=\"numeric\" step=\"any\"  aria-invalid=\"false\" aria-required=true><\/div><\/div><div class='ff-el-group'><div class=\"ff-el-input--label ff-el-is-required asterisk-right\"><label for='ff_16_urine_creatinine' id='label_ff_16_urine_creatinine' aria-label=\"Urine Creatinine\">Urine Creatinine<\/label><\/div><div class='ff-el-input--content'><input type=\"number\" name=\"urine_creatinine\" id=\"ff_16_urine_creatinine\" class=\"ff-el-form-control\" placeholder=\"value in mg\/dL\" data-name=\"urine_creatinine\" inputmode=\"numeric\" step=\"any\"  aria-invalid=\"false\" aria-required=true><\/div><\/div><div class='ff-el-group'><div class=\"ff-el-input--label asterisk-right\"><label for='ff_16_numeric-field_5' id='label_ff_16_numeric-field_5' aria-label=\"Fractional Excretion of Sodium (value in %)\">Fractional Excretion of Sodium (value in %)<\/label><\/div><div class='ff-el-input--content'><input type=\"text\" name=\"numeric-field_5\" id=\"ff_16_numeric-field_5\" class=\"ff-el-form-control  ff_has_formula ff_numeric\" placeholder=\"FeNa value\" data-name=\"numeric-field_5\" data-calculation_formula=\"(({input.urine_sodium}*{input.serum_creatinine}) \/ ({input.serum_sodium}*{input.urine_creatinine})) * 100\" readonly=\"1\" data-formatter=\"{&quot;decimal&quot;:&quot;.&quot;,&quot;separator&quot;:&quot;,&quot;,&quot;precision&quot;:2,&quot;symbol&quot;:&quot;&quot;}\"  aria-invalid=\"false\" aria-required=false><\/div><\/div><div class='ff-el-group ff-text-left ff_submit_btn_wrapper'><button type=\"submit\" class=\"ff-btn ff-btn-submit ff-btn-lg ff_btn_style\"  aria-label=\"Calculate FENa\">Calculate FENa<\/button><\/div><\/fieldset><\/form><div id='fluentform_16_errors' class='ff-errors-in-stack ff_form_instance_16_1 ff-form-loading_errors ff_form_instance_16_1_errors'><\/div><\/div>            <script type=\"text\/javascript\">\n                window.fluent_form_ff_form_instance_16_1 = {\"id\":\"16\",\"settings\":{\"layout\":{\"labelPlacement\":\"top\",\"helpMessagePlacement\":\"with_label\",\"errorMessagePlacement\":\"inline\",\"asteriskPlacement\":\"asterisk-right\"},\"restrictions\":{\"denyEmptySubmission\":{\"enabled\":false}}},\"form_instance\":\"ff_form_instance_16_1\",\"form_id_selector\":\"fluentform_16\",\"rules\":{\"serum_sodium\":{\"required\":{\"value\":true,\"message\":\"This field is required\"},\"numeric\":{\"value\":true,\"message\":\"This field must contain numeric value\"},\"min\":{\"value\":\"\",\"message\":\"Minimum value is \"},\"max\":{\"value\":\"\",\"message\":\"Maximum value is \"}},\"serum_creatinine\":{\"required\":{\"value\":true,\"message\":\"This field is required\"},\"numeric\":{\"value\":true,\"message\":\"This field must contain numeric value\"},\"min\":{\"value\":\"\",\"message\":\"Minimum value is \"},\"max\":{\"value\":\"\",\"message\":\"Maximum value is \"}},\"urine_sodium\":{\"required\":{\"value\":true,\"message\":\"This field is required\"},\"numeric\":{\"value\":true,\"message\":\"This field must contain numeric value\"},\"min\":{\"value\":\"\",\"message\":\"Minimum value is \"},\"max\":{\"value\":\"\",\"message\":\"Maximum value is \"}},\"urine_creatinine\":{\"required\":{\"value\":true,\"message\":\"This field is required\"},\"numeric\":{\"value\":true,\"message\":\"This field must contain numeric value\"},\"min\":{\"value\":\"\",\"message\":\"Minimum value is \"},\"max\":{\"value\":\"\",\"message\":\"Maximum value is \"}},\"numeric-field_5\":{\"required\":{\"value\":false,\"message\":\"This field is required\"},\"numeric\":{\"value\":true,\"message\":\"This field must contain numeric value\"},\"min\":{\"value\":\"\",\"message\":\"Minimum value is \"},\"max\":{\"value\":\"\",\"message\":\"Maximum value is \"}}},\"debounce_time\":300};\n                            <\/script>\n            \n<blockquote>\n<p>Formula for <b>FENa<\/b> in \u00a0% = \u00a0[(P<sub>Cr<\/sub>\u00a0\u00d7 U<sub>Na<\/sub>\u00a0) \/ (P<sub>Na<\/sub>\u00a0\u00d7 U<sub>Cr<\/sub>)] x 100<\/p>\n<\/blockquote>\n<p>PCr plasma creatinine, UNa urine sodium, PNa plasma sodium, and UCr urine creatinine<\/p>\n\n<h2>Interpretation of FENa<\/h2>\n<p>Renal handling of sodium (filtered sodium) provides supportive information about the possible etiology of <b>acute kidney injury<\/b>.<\/p>\n\n<table id=\"tablepress-29\" class=\"tablepress tablepress-id-29\">\n<tbody>\n<tr class=\"row-1\">\n\t<td class=\"column-1\">FENa value<\/td><td class=\"column-2\">UNa (mmol\/L)<\/td><td class=\"column-3\">Cause of renal injury<\/td><td class=\"column-4\">Etiology<\/td>\n<\/tr>\n<tr class=\"row-2\">\n\t<td class=\"column-1\"><1%<\/td><td class=\"column-2\"><20<\/td><td class=\"column-3\">Pre-renal AKI<\/td><td class=\"column-4\">1. Congestive heart failure<br \/>\n2. Renal Artery Stenosis<br \/>\n3. Septic Shock<br \/>\n4. Hypovolemia<br \/>\n5. Hepatorenal syndrome<br \/>\n<\/td>\n<\/tr>\n<tr class=\"row-3\">\n\t<td class=\"column-1\">1-4%<\/td><td class=\"column-2\">>40<\/td><td class=\"column-3\">Intrinsic renal injury<\/td><td class=\"column-4\">1. Acute Tubular Necrosis<br \/>\n2. Acute interstitial nephritis<br \/>\n3. Glomerulonephritis<br \/>\n<\/td>\n<\/tr>\n<tr class=\"row-4\">\n\t<td class=\"column-1\">>4% <\/td><td class=\"column-2\">>40<\/td><td class=\"column-3\">Post-renal AKI<\/td><td class=\"column-4\">Obstructive uropathy (ureteric urolithiasis, benign prostatic hyperplasia)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<!-- #tablepress-29 from cache -->\n<p>AKI Acute Kidney Injury,\u00a0UNa Spot urine Sodium<\/p>\n<h2>Application<\/h2>\n<p>This calculator is used for distinguishing between the various causes of AKI (pre-renal, post-renal, or intrinsic\/renal causes).<\/p>\n<h2>Limitations<\/h2>\n<p>FENa estimation is likely to be inaccurate in the setting of uncontrolled glucosuria (<a href=\"https:\/\/myendoconsult.com\/learn\/diabetes-mellitus\/\">diabetes mellitus)<\/a>, concomitant diuretic exposure, known chronic kidney disease, or known obstructive uropathy. For patients taking diuretics, <b>fractional excretion of urea<\/b> is recommended. This is due to the natriuresis induced by diuretics.<\/p>\n<h2>References<\/h2>\n<ul>\n<li>Espinel CH. The FENa test. Use in the differential diagnosis of acute renal failure. <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/947239\/\" target=\"_blank\" rel=\"noopener\">JAMA. 1976 Aug 9;236(6):579-81. doi: 10.1001\/jama.236.6.579. PMID: 947239.<\/a><\/li>\n<li>Kaplan AA, Kohn OF. Fractional excretion of urea as a guide to renal dysfunction. <a href=\"https:\/\/www.karger.com\/article\/Abstract\/168417\" target=\"_blank\" rel=\"noopener\">Am J Nephrol. 1992;12(1-2):49-54. doi: 10.1159\/000168417. PMID: 1415365.<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>The Fractional Excretion of Sodium Calculation (FENa) requires the following patient parameters : Plasma Sodium and Urine Sodium in mEq\/L. Plasma Creatinine and Urine Creatinine in mg\/dL. Formula for FENa in \u00a0% = \u00a0[(PCr\u00a0\u00d7 UNa\u00a0) \/ (PNa\u00a0\u00d7 UCr)] x 100 PCr plasma creatinine, UNa urine sodium, PNa plasma sodium, and UCr urine creatinine Interpretation of [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[100],"tags":[],"class_list":["post-844257","post","type-post","status-publish","format-standard","hentry","category-endocalculator","post-wrapper","thrv_wrapper"],"_links":{"self":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/posts\/844257","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/comments?post=844257"}],"version-history":[{"count":74,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/posts\/844257\/revisions"}],"predecessor-version":[{"id":4415912,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/posts\/844257\/revisions\/4415912"}],"wp:attachment":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/media?parent=844257"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/categories?post=844257"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/tags?post=844257"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}