{"id":63166,"date":"2022-05-02T16:30:59","date_gmt":"2022-05-02T06:30:59","guid":{"rendered":"https:\/\/www.horsemagazine.com\/thm\/?p=63166"},"modified":"2022-05-02T16:32:04","modified_gmt":"2022-05-02T06:32:04","slug":"reading-blood-tests-with-david-ramey","status":"publish","type":"post","link":"https:\/\/www.horsemagazine.com\/thm\/2022\/05\/reading-blood-tests-with-david-ramey\/","title":{"rendered":"Reading Blood Tests with David Ramey"},"content":{"rendered":"<ul>\n<li>with \u00a0\u2028<a href=\"https:\/\/www.doctorramey.com\/author\/drramey\/\">David Ramey<\/a><\/li>\n<\/ul>\n<p>THM is privileged to share this important article by one of our very favourite veterinary writers, David Ramey DVM. David&#8217;s website <a href=\"https:\/\/www.doctorramey.com\">https:\/\/www.doctorramey.com<\/a> is filled with scores of thoughfully written, often challenging, articles on horses and their veterinary care. Do yourself a favour and check it out&#8230; over to David:<\/p>\n<p>I think it\u2019s time to talk a little bit about blood tests for horses.\u00a0 Not each and every individual blood test, of course \u2013 that would be a number that would almost be too large to count.\u00a0 Books have been written about such topics.\u00a0 Rather, let\u2019s discuss a little about more general interpretation of blood tests.<\/p>\n<p>The reason I bring this up is that I find many clients \u2013 and even some veterinarians \u2013 will look at laboratory blood test results in something of a vacuum.\u00a0 So, for example, a concerned owner will ask for a copy of blood test results (results that they have a perfect right to see, of course), look for \u201chighs\u201d and \u201clows,\u201d and then try to come up with some sort of reason for the \u201cabnormality.\u201d\u00a0 First, let\u2019s look at a lab test.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-63169\" src=\"https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ReadingRameyDiagram.jpg\" alt=\"\" width=\"727\" height=\"642\" srcset=\"https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ReadingRameyDiagram.jpg 727w, https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ReadingRameyDiagram-300x265.jpg 300w, https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ReadingRameyDiagram-340x300.jpg 340w\" sizes=\"auto, (max-width: 727px) 100vw, 727px\" \/><\/p>\n<p>You\u2019ll notice that by each of the values, there\u2019s a little bar graph.\u00a0 It\u2019s divided into thirds, with the middle third being the lab \u201cnormal.\u201d\u00a0 Everything else is either above or below the lab normal.\u00a0 In case you\u2019re wondering, this little bar graph is called the reference interval (RI).<\/p>\n<p>The problem is that lab tests aren\u2019t always as easy to interpret as just looking at a bar.\u00a0 Herein begins one of the big problems that some people have when it comes to reading blood tests.\u00a0 Someone who is inclined to be attracted to simple explanations might look at the test and say, \u201cWow, the horse\u2019s sodium, chloride, and GGT are below normal.\u00a0 I wonder what\u2019s wrong?\u201d\u00a0 Which, honestly, is not an unreasonable question.\u00a0 However, the answer is most likely, \u201cNothing.\u201d\u00a0 Here\u2019s why.<\/p>\n<p>Lab \u201cnormal ranges\u201d are simply an average of many blood samples.\u00a0 The bar, as it were, is moved both above and below the average (this is a matter for statisticians).\u00a0 Moving the bar up and down eventually produces a group that includes 95% of the subjects studied.\u00a0 Another way to look at the normal range is that 95% of the horses should fall in that range.\u00a0 That\u2019s great, as far as it goes.<\/p>\n<p>The problem \u2013 insofar as overinterpreting tests goes \u2013 is that there are still at least 5% of the normal population of horses that fall on either side of the laboratory normal reference interval that may still be perfectly healthy.\u00a0 Unfortunately, when some lab finding falls just outside of the laboratory RI, an individual can get diagnosed (and sometimes treated) as \u201cabnormal.\u201d<\/p>\n<p>The thing is, \u201cNormal\u201d is not an absolute condition:\u00a0 it\u2019s relative to the overall well-being of your horse. \u00a0\u201cNormal\u201d typically lacks any sort of a universal definition.\u00a0 Take your horse\u2019s front legs.\u00a0 Does he toe in?\u00a0 Toe out?\u00a0 Are his legs perfectly straight?\u00a0 What\u2019s normal?<\/p>\n<p>Blood tests work that way, too.\u00a0 It\u2019s entirely possible for your normal, healthy horse to have a blood test that\u2019s on either side of the laboratory range.\u00a0 It\u2019s not necessarily abnormal.\u00a0 Here are a couple of examples.<\/p>\n<ul>\n<li>You submit a complete blood count for your horse because you want to see how he\u2019s doing (not necessarily a good reason, but it happens). A complete blood count (CBC) looks at things like the total number of red and white blood cells and the amount of protein in the blood. The laboratory range is 6.3 to 10.9 M\/\u00b5L (if you like these sorts of units, you were probably very good in chemistry).\u00a0 Your horse\u2019s level is 6.0.\u00a0 Is this something that you need to do something about?\u00a0 Is he anemic (that is, does he lack red blood cells)?<\/li>\n<li>Take the test that I posted earlier. Let\u2019s say it\u2019s summertime and it\u2019s been hot. \u00a0You have some blood drawn because you\u2019re worried about him. His sodium and his chloride \u2013 important salts, to be sure \u2013 are just below the lab \u201cnormal.\u201d\u00a0 Should you start giving him salt?<\/li>\n<\/ul>\n<p>If your horse seems otherwise healthy, the answer to both questions is almost always going to be, \u201cNo.\u201d\u00a0 In the absence of any other signs of a problem, something that\u2019s just over or under the laboratory \u201cnormal\u201d isn\u2019t likely to be abnormal, that is, it isn\u2019t likely to be anything to worry about.\u00a0 It\u2019s more likely to just be normal for your horse at the time that the test was taken \u2013 and that doesn\u2019t even get into possibly problems with the way that the sample was handled.<\/p>\n<p>Overinterpretation of blood tests can go the other way, too.\u00a0 So, for example, say you have an older horse that you\u2019re concerned might have Pars Pituitary Intermedia Disorder (mercifully abbreviated as PPID and more commonly known as Equine Cushing\u2019s Disease).\u00a0 Let\u2019s say you run a screening test for ACTH (which is one of the more commonly performed tests) and the lab test comes back at the high end of the laboratory\u2019s normal range (for the lab that I use, the normal range is 9 \u2013 35 pg\/mL).\u00a0 Let\u2019s say that your horse\u2019s test reads 34 pg\/mL.\u00a0 Does that mean that he\u2019s close to developing PPID?\u00a0 Does that mean you need to start him on medication?\u00a0 Nope.\u00a0 In the absence of any other clinical signs, it most likely means that on that day, he was at the higher end of the laboratory\u2019s normal range.\u00a0 If you\u2019re still worried, you can always run another test somewhere down the road.\u00a0 In and of themselves, if your horse seems otherwise normal, he probably is.<\/p>\n<p>All of this can lead to a bigger problem that besets the horse world (and one about which I\u2019ll get around to writing soon).\u00a0 That problem is known as \u201cMedicalization\u201d (also known as \u201cDisease mongering\u201d).\u00a0 Medicalization occurs when some normal variation gets labelled as absolutely abnormal and a treatment gets prescribed, accordingly.\u00a0 If a normal health variation is taken as some sort of pathologic state, it opens the door to all sorts of needless and expensive treatments, big profits for sellers of those treatments, and empty wallets for horse owners, all without the slightest benefit for horses.<\/p>\n<p>Of course, blood tests are very useful.\u00a0 If your horse is running a fever, has a snotty nose, has a cough, and isn\u2019t eating, a blood test showing an elevated white blood cell count and increase inflammatory proteins has meaning.\u00a0 If you horse has a curly hair coat, won\u2019t shed, and is 23 years old, an elevated ACTH level is likely to mean something.\u00a0 But in the absence of other signs of a problem, some laboratory result that\u2019s on the border of what a laboratory has established as \u201cnormal\u201d is more likely than not to be normal for your horse.<\/p>\n<p><strong>BOTTOM LINE:<\/strong>\u00a0 If your horse is otherwise healthy, you probably don\u2019t need to worry too much about some lab value that\u2019s near the top or the bottom of a laboratory established reference range.\u00a0 Your horse probably doesn\u2019t like having needles stuck in him anyway.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-large wp-image-63172\" src=\"https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ARIAT-Advert-May2021-744x1024.jpg\" alt=\"\" width=\"584\" height=\"804\" srcset=\"https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ARIAT-Advert-May2021-744x1024.jpg 744w, https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ARIAT-Advert-May2021-218x300.jpg 218w, https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ARIAT-Advert-May2021-768x1057.jpg 768w, https:\/\/www.horsemagazine.com\/thm\/wp-content\/uploads\/2022\/05\/ARIAT-Advert-May2021.jpg 819w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Blood tests and their uses and abuses. Dr David Ramey explains how and when to use a blood test from your favourite horse. It&#8217;s great reading &#8211; and a great help especially for your horse&#8230;<\/p>\n","protected":false},"author":10,"featured_media":63171,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"nf_dc_page":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[81,37],"tags":[2340,2342,2341],"class_list":["post-63166","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-breaking-news","category-horse-care-and-health","tag-blood-tests","tag-david-ramey","tag-veterinary-advice"],"acf":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/posts\/63166","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/comments?post=63166"}],"version-history":[{"count":5,"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/posts\/63166\/revisions"}],"predecessor-version":[{"id":63174,"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/posts\/63166\/revisions\/63174"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/media\/63171"}],"wp:attachment":[{"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/media?parent=63166"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/categories?post=63166"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.horsemagazine.com\/thm\/wp-json\/wp\/v2\/tags?post=63166"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}