{"id":4129,"date":"2021-09-10T08:00:00","date_gmt":"2021-09-10T01:00:00","guid":{"rendered":"https:\/\/drsoaraweeurology.com\/?p=4129"},"modified":"2026-08-28T01:24:05","modified_gmt":"2026-08-27T18:24:05","slug":"urina-residua-perche-misuriamo","status":"publish","type":"post","link":"https:\/\/drsoaraweeurology.com\/it\/2021\/09\/10\/residual-urine-why-we-measure\/","title":{"rendered":"Residual Urine: What the Number Means, and What It Cannot Tell You"},"content":{"rendered":"\n<div class=\"wp-block-columns coblocks-author-columns has-background is-layout-flex wp-container-core-columns-is-layout-52275889 wp-block-columns-is-layout-flex\" style=\"background-color:#8C8C971A;padding-top:2.5rem;padding-right:2.5rem;padding-bottom:2.5rem;padding-left:2.5rem\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:25%\">\n<figure class=\"wp-block-image size-full is-style-rounded\"><img data-recalc-dims=\"1\" fetchpriority=\"high\" decoding=\"async\" width=\"800\" height=\"800\" data-attachment-id=\"7037\" data-permalink=\"https:\/\/drsoaraweeurology.com\/it\/new-photo-2024\/\" data-orig-file=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?fit=800%2C800&amp;ssl=1\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Dr. Soarawee Weerasopone \u2014 Board-Certified Urologist in Bangkok, Thailand\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;Dr. Soarawee Weerasopone \u2014 Board-Certified Urologist in Bangkok, Thailand&lt;\/p&gt;\n\" data-large-file=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?fit=800%2C800&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?resize=800%2C800&#038;ssl=1\" alt=\"Best Urologist working in Chonburi and Cambodia\" class=\"wp-image-7037\" srcset=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?w=800&amp;ssl=1 800w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?resize=12%2C12&amp;ssl=1 12w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?resize=600%2C600&amp;ssl=1 600w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?resize=400%2C400&amp;ssl=1 400w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2023\/12\/New-Photo-2024.png?resize=200%2C200&amp;ssl=1 200w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:75%\">\n<p class=\"wp-block-paragraph\"><strong><a href=\"https:\/\/drsoaraweeurology.com\/\" target=\"_blank\" rel=\"noreferrer noopener\">Soarawee Weerasopone, Urologist<\/a><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.bangkokhospital.com\/en\/bangkok\/doctor\/dr-soarawee-weerasopone-2\" target=\"_blank\" rel=\"noreferrer noopener\">Bangkok hospital Headquarter, Bangkok<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"tel:+66880221445\" target=\"_blank\" rel=\"noreferrer noopener\">Samitivej Sriracha Hospital \u2014 Urology department: <strong>088-022-1445<\/strong><\/a><\/p>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button is-style-outline is-style-outline--1\"><a class=\"wp-block-button__link has-background-background-color has-text-color has-background has-link-color has-small-font-size has-custom-font-size wp-element-button\" href=\"https:\/\/www.bangkokhospital.com\/en\/bangkok\/doctor\/dr-soarawee-weerasopone-2\" style=\"color:#1b4965\" target=\"_blank\" rel=\"noreferrer noopener\">Book a Consultation<\/a><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<ul class=\"wp-block-social-links aligncenter has-normal-icon-size is-style-default coblocks-animate is-content-justification-center is-layout-flex wp-container-core-social-links-is-layout-3e41869c 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1-.064.262c-.13.523-.402.913-.815 1.17-.413.255-.95.382-1.61.382z\"\/>\n    <\/svg>\n  <\/a>\n  \n  <a href=\"https:\/\/orcid.org\/0009-0004-8387-3559\" \n     target=\"_blank\" \n     rel=\"noopener\"\n     title=\"ORCID iD\"\n     aria-label=\"View ORCID Profile\"\n     style=\"text-decoration: none; color: #A6CE39; transition: transform 0.2s; display: inline-block;\"\n     onmouseover=\"this.style.transform='scale(1.15)'\"\n     onmouseout=\"this.style.transform='scale(1)'\">\n    <svg width=\"28\" height=\"28\" viewBox=\"0 0 24 24\" fill=\"currentColor\">\n      <path d=\"M12 0C5.372 0 0 5.372 0 12s5.372 12 12 12 12-5.372 12-12S18.628 0 12 0zM7.369 4.378c.525 0 .947.431.947.947 0 .525-.422.947-.947.947-.525 0-.946-.422-.946-.947 0-.525.421-.947.946-.947zm-.722 3.038h1.444v10.041H6.647V7.416zm3.562 0h3.9c3.712 0 5.344 2.653 5.344 5.025 0 2.578-2.016 5.025-5.325 5.025h-3.919V7.416zm1.444 1.303v7.444h2.297c3.272 0 4.022-2.484 4.022-3.722 0-2.016-1.284-3.722-4.097-3.722h-2.222z\"\/>\n    <\/svg>\n  <\/a>\n  \n  <a href=\"https:\/\/scholar.google.com\/citations?user=lTgsRMUAAAAJ&#038;hl=en\" \n     target=\"_blank\" \n     rel=\"noopener\"\n     title=\"Google Scholar\"\n     aria-label=\"View Google Scholar Profile\"\n     style=\"text-decoration: none; color: #4285F4; transition: transform 0.2s; display: inline-block;\"\n     onmouseover=\"this.style.transform='scale(1.15)'\"\n     onmouseout=\"this.style.transform='scale(1)'\">\n    <svg width=\"28\" height=\"28\" viewBox=\"0 0 24 24\" fill=\"currentColor\">\n      <path d=\"M5.242 13.769L0.5 9.5 12 1l11.5 8.5-4.742 4.269C17.548 11.249 14.978 9.5 12 9.5c-2.977 0-5.548 1.748-6.758 4.269zM12 10a7 7 0 1 0 0 14 7 7 0 0 0 0-14z\"\/>\n    <\/svg>\n  <\/a>\n  \n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Patients ask this constantly: why does the doctor want a scan of my bladder <em>after<\/em> I have emptied it? The answer is that emptying and passing urine are not the same thing. A bladder can produce a respectable stream and still leave a substantial volume behind, and that stagnant urine is what causes infections, stones and, at the extreme, pressure on the kidneys.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Urology center Bangkok hospital Thailand\u00a0<a href=\"https:\/\/www.bangkokhospital.com\/en\/bangkok\/doctor\/dr-soarawee-weerasopone-2\" target=\"_blank\" rel=\"noreferrer noopener\">Booking online<\/a>\u00a0<a href=\"tel:02-310-3009\">02-310-3009<\/a>\u00a0<a href=\"mailto:bhquro@bdms.co.th\">bhquro@bdms.co.th<\/a><\/li>\n\n\n\n<li>Samitivej Sriracha hospital Chonburi&nbsp;<a href=\"tel:088-022-1445\">088-022-1445<\/a><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">How it is measured<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">It used to mean passing a catheter after you had finished, which was accurate and unpleasant. <strong>Ultrasound has replaced it<\/strong>: the bladder is scanned, you go to the toilet, and it is scanned again. The result is the volume left behind, in millilitres, without anything being inserted.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Two things affect the accuracy, and both are worth knowing because they are the reason a surprising result should not be acted on immediately.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>The second scan must follow quickly<\/strong> \u2014 within about ten minutes. The kidneys keep producing urine, so a delayed scan measures new urine as well as leftover urine and overstates the result.<\/li>\n\n\n\n<li><strong>It depends on who is scanning.<\/strong> The volume is calculated from measured bladder dimensions, so technique matters.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Practically: come with a comfortably full bladder and do not empty it in the waiting room, or the test cannot be done and you will be sent away to drink and come back.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img data-recalc-dims=\"1\" decoding=\"async\" width=\"800\" height=\"534\" data-attachment-id=\"4140\" data-permalink=\"https:\/\/drsoaraweeurology.com\/it\/2021\/09\/10\/residual-urine-why-we-measure\/man-is-standing-pee-in-a-toilet-healthcare-urinal-concept\/\" data-orig-file=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Void.jpg?fit=1200%2C801&amp;ssl=1\" data-orig-size=\"1200,801\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;4&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;NIKON D610&quot;,&quot;caption&quot;:&quot;Man is standing pee in a toilet - healthcare urinal concept&quot;,&quot;created_timestamp&quot;:&quot;1548491249&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;46&quot;,&quot;iso&quot;:&quot;2000&quot;,&quot;shutter_speed&quot;:&quot;0.033333333333333&quot;,&quot;title&quot;:&quot;Man is standing pee in a toilet - healthcare urinal concept&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Now a day, residual urine measurement is done by ultrasonography which is a lot more convenience.\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;Now a day, residual urine measurement is done by ultrasonography which is a lot more convenience.&lt;\/p&gt;\n\" data-large-file=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Void.jpg?fit=800%2C534&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Void.jpg?resize=800%2C534&#038;ssl=1\" alt=\"Bladder ultrasound performed after voiding to measure residual urine volume\" class=\"wp-image-4140\" srcset=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Void.jpg?w=1200&amp;ssl=1 1200w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Void.jpg?resize=300%2C200&amp;ssl=1 300w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Void.jpg?resize=1024%2C684&amp;ssl=1 1024w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Void.jpg?resize=768%2C513&amp;ssl=1 768w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Void.jpg?resize=18%2C12&amp;ssl=1 18w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Scan, void, scan again \u2014 and the second scan has to follow promptly.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">A single reading should not decide anything<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This was absent from the earlier version and is the most important addition to the page.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Residual volume varies enormously in the same person from one void to the next.<\/strong> How much you had drunk, how long you had held on, how relaxed you were, whether the clinic toilet felt private \u2014 all of it moves the number. A man can measure 250 mL on one visit and 40 mL on the next with nothing having changed.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So a single high reading is a reason to <strong>repeat the measurement<\/strong>, not a reason to start treatment. And a result is only meaningful if a reasonable volume was actually passed: emptying 60 mL and leaving 60 mL behind tells you nothing about the bladder, because the bladder was never properly full to begin with \u2014 the same principle that governs <a href=\"https:\/\/drsoaraweeurology.com\/2023\/04\/23\/uroflowmetry\/\">flow testing<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What the numbers mean<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Under about 50 mL<\/strong> \u2014 emptying well.<\/li>\n\n\n\n<li><strong>Over about 200 mL<\/strong> \u2014 emptying poorly, and worth acting on.<\/li>\n\n\n\n<li><strong>In between<\/strong> \u2014 the range the earlier version left unaddressed, and where most results actually fall. It is interpreted alongside symptoms, flow rate, kidney function and whether infections keep occurring, rather than treated as a verdict in itself.<\/li>\n\n\n\n<li><strong>In children<\/strong>, the threshold is lower and paediatric assessment differs.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The earlier version presented a separate normal range of 50 to 100 mL for older people. <strong>That has been softened<\/strong>: residual volumes do tend to rise with age, but this is a tendency rather than an established age-specific normal, and a raised residual in an older man is not automatically to be accepted as age. <strong>These figures are guides for interpretation, not diagnostic cut-offs.<\/strong> Persistently over about 100 mL is associated with more urinary infections, which is a practical reason to take repeated moderate elevations seriously.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What the number cannot tell you<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Also absent from the earlier version, and the reason the measurement is a starting point rather than an answer.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>A high residual volume does not say why the bladder is not emptying<\/strong>, and there are two quite different explanations that look identical on the scan:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>The outlet is blocked<\/strong> \u2014 an <a href=\"https:\/\/drsoaraweeurology.com\/2020\/08\/28\/benign-prostate-bph\/\">enlarged prostate<\/a> or a <a href=\"https:\/\/drsoaraweeurology.com\/2021\/05\/14\/urethral-stricture-narrow-urethra\/\">urethral stricture<\/a>.<\/li>\n\n\n\n<li><strong>The bladder muscle is weak<\/strong> \u2014 from long-standing obstruction, diabetes affecting the nerves, neurological disease, or age.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The distinction decides the treatment, and getting it wrong matters: <strong>an operation on the prostate of a man whose real problem is a weak bladder does not fix his emptying.<\/strong> Where it is unclear, pressure-flow studies settle it. Medication is also worth reviewing before anything else \u2014 anticholinergics, older antihistamines, decongestants and opioids all impair emptying, as set out under <a href=\"https:\/\/drsoaraweeurology.com\/2021\/05\/28\/transient-urinary-retention\/\">causes of retention<\/a>.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img data-recalc-dims=\"1\" decoding=\"async\" width=\"800\" height=\"533\" data-attachment-id=\"4141\" data-permalink=\"https:\/\/drsoaraweeurology.com\/it\/2021\/09\/10\/residual-urine-why-we-measure\/urethral-catheter-hold-on-blue-glove-hand-on-white-background-5\/\" data-orig-file=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Catheter.jpg?fit=1200%2C800&amp;ssl=1\" data-orig-size=\"1200,800\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;5.6&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;Canon EOS Kiss X2&quot;,&quot;caption&quot;:&quot;urethral catheter hold on blue glove hand on white background&quot;,&quot;created_timestamp&quot;:&quot;1567694652&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;60&quot;,&quot;iso&quot;:&quot;100&quot;,&quot;shutter_speed&quot;:&quot;0.005&quot;,&quot;title&quot;:&quot;urethral catheter hold on blue glove hand on white background&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"In the past, we do residual urine measurement by intermittent urethral catheterization which is quite too invasive.\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;In the past, we do residual urine measurement by intermittent urethral catheterization which is quite too invasive.&lt;\/p&gt;\n\" data-large-file=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Catheter.jpg?fit=800%2C534&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Catheter.jpg?resize=800%2C533&#038;ssl=1\" alt=\"Urethral catheter, the older invasive method of measuring residual urine now replaced by ultrasound\" class=\"wp-image-4141\" srcset=\"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Catheter.jpg?w=1200&amp;ssl=1 1200w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Catheter.jpg?resize=300%2C200&amp;ssl=1 300w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Catheter.jpg?resize=1024%2C683&amp;ssl=1 1024w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Catheter.jpg?resize=768%2C512&amp;ssl=1 768w, https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2021\/09\/Catheter.jpg?resize=18%2C12&amp;ssl=1 18w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">The catheter method was accurate and unpleasant; ultrasound gives the same figure without it.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Symptoms that need attention the same day<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In an emergency in Thailand, call <strong>1669<\/strong>.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Complete inability to pass urine<\/strong> with a painful full lower abdomen.<\/li>\n\n\n\n<li><strong>Fever or shaking chills<\/strong> with difficulty passing urine.<\/li>\n\n\n\n<li><strong>Constant dribbling with a full, uncomfortable abdomen<\/strong> \u2014 an overflowing bladder rather than an improvement.<\/li>\n\n\n\n<li><strong>A very large residual with rising kidney blood tests<\/strong>, which needs draining rather than observing.<\/li>\n\n\n\n<li><strong>New leg weakness or numbness, or loss of bowel control<\/strong>, alongside difficulty emptying \u2014 an emergency measured in hours.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Frequently Asked Questions About Residual Urine<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">What is residual urine and why is it measured?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">It is the volume left in the bladder after you have finished passing urine. It is measured because a good stream does not prove good emptying, and urine left behind causes infections, stones and, at the extreme, pressure on the kidneys.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">My result was high. Does that mean I need treatment?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Not on one reading. Residual volume varies substantially between voids depending on fluid intake, how long you held on and how relaxed you were, so a high result is a reason to repeat the measurement rather than to start treatment. The result also only means something if a reasonable volume was passed.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What counts as normal?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Under about 50 mL is good emptying and over about 200 mL is poor. Most results fall in between and are interpreted alongside symptoms, flow rate, kidney function and any history of infection. Persistently over about 100 mL is associated with more urinary infections. These figures guide interpretation rather than serving as diagnostic cut-offs.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Does a high residual mean my prostate needs an operation?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Not necessarily. A blocked outlet and a weak bladder muscle produce identical results on the scan, and operating on the prostate of a man whose bladder is the real problem does not improve his emptying. Pressure-flow studies distinguish them, and medication that impairs emptying should be reviewed first.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How should I prepare?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Arrive with a comfortably full bladder and do not empty it in the waiting room. The second scan must follow within about ten minutes of voiding, since the kidneys keep producing urine and a delayed scan overstates the result.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Arranging a consultation<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Dr. Soarawee Weerasopone sees patients at <a href=\"https:\/\/www.bangkokhospital.com\/en\/bangkok\/doctor\/dr-soarawee-weerasopone-2\">Bangkok Hospital Headquarters<\/a> and at Samitivej Sriracha Hospital in Chonburi on <a href=\"tel:0880221445\">088-022-1445<\/a>. Bring any previous residual measurements and flow tests with their dates, and a full list of your medicines \u2014 several common drugs impair bladder emptying and are worth excluding before anything else is considered.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bangkok Hospital Telemedicine is available for patients who cannot attend in person, including international patients \u2014 arrange it in advance by email to the Urology department at <a href=\"mailto:bhquro@bdms.co.th\">bhquro@bdms.co.th<\/a>. Samitivej Sriracha is in-person only. Enquiries about cost are answered by the hospital, not by this website.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Disclaimer:<\/strong> This content is written and reviewed by Dr. Soarawee Weerasopone, a board-certified urologist at Bangkok Hospital Headquarters, and is intended for education only. It is not medical advice, diagnosis or a prescription for any individual, and no advice, diagnosis or prescription is given through personal messaging channels or social media. Dr. Soarawee operates no public social media account; any account offering private consultation in his name is fraudulent. In an emergency in Thailand, call <strong>1669<\/strong>.<\/p>\n\n\n\n<script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@graph\": [\n    {\n      \"@type\": \"MedicalWebPage\",\n      \"@id\": \"https:\/\/drsoaraweeurology.com\/2021\/09\/24\/residual-urine-why-we-measure\/#webpage\",\n      \"url\": \"https:\/\/drsoaraweeurology.com\/2021\/09\/24\/residual-urine-why-we-measure\/\",\n      \"name\": \"Residual Urine: What the Number Means, and What It Cannot Tell You\",\n      \"description\": \"Post-void residual urine measurement by bladder ultrasound: interpretation thresholds, the substantial intra-individual variability that requires repeat measurement, and the inability of the result to distinguish obstruction from detrusor underactivity.\",\n      \"inLanguage\": \"en\",\n      \"datePublished\": \"2021-09-24\",\n      \"dateModified\": \"2026-08-27\",\n      \"isPartOf\": { \"@id\": \"https:\/\/drsoaraweeurology.com\/#website\" },\n      \"author\": { \"@id\": \"https:\/\/drsoaraweeurology.com\/#physician\" },\n      \"reviewedBy\": { \"@id\": \"https:\/\/drsoaraweeurology.com\/#physician\" },\n      \"publisher\": { \"@id\": \"https:\/\/drsoaraweeurology.com\/#physician\" },\n      \"about\": { \"@id\": \"https:\/\/drsoaraweeurology.com\/2021\/09\/24\/residual-urine-why-we-measure\/#pvr\" },\n      \"audience\": { \"@type\": \"MedicalAudience\", \"audienceType\": \"Patient\" },\n      \"disambiguatingDescription\": \"The earlier version presented threshold values without stating that post-void residual varies substantially between voids in the same individual, so that a single elevated reading warrants repetition rather than treatment, and without noting that the result is uninterpretable if only a small volume was voided. 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Useful \u2014 but it varies hugely between visits, a single reading should not decide anything, and it never explains why the bladder is not emptying.<\/p>","protected":false},"author":185281453,"featured_media":10090,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"How post-void residual urine is measured, why a single reading should be repeated before acting on it, and why a high result cannot distinguish obstruction from a weak bladder.","jetpack_seo_html_title":"Residual Urine Measurement Explained | Dr. Soarawee Bangkok","jetpack_seo_noindex":false,"jetpack_seo_schema_type":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_wpcom_ai_launchpad_first_post":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"{title}\n\n{excerpt}\n\n{url}","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"_wpas_customize_per_network":false,"jetpack_post_was_ever_published":false},"categories":[1362],"tags":[1550,1549,1551],"class_list":["post-4129","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-infection","tag-infectious-clinic","tag-residual-urine","tag-urology-clinic"],"jetpack_publicize_connections":[],"jetpack_likes_enabled":false,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/pgZdrK-14B","jetpack_featured_media_url":"https:\/\/i0.wp.com\/drsoaraweeurology.com\/wp-content\/uploads\/2026\/04\/Residual-Urine-Test.webp?fit=1200%2C630&ssl=1","_links":{"self":[{"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/posts\/4129","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/users\/185281453"}],"replies":[{"embeddable":true,"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/comments?post=4129"}],"version-history":[{"count":19,"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/posts\/4129\/revisions"}],"predecessor-version":[{"id":11756,"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/posts\/4129\/revisions\/11756"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/media\/10090"}],"wp:attachment":[{"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/media?parent=4129"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/categories?post=4129"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/drsoaraweeurology.com\/it\/wp-json\/wp\/v2\/tags?post=4129"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}