{"id":9679,"date":"2024-09-10T01:52:18","date_gmt":"2024-09-09T22:52:18","guid":{"rendered":"https:\/\/medilab.km.ua\/?p=9679"},"modified":"2026-04-20T18:55:27","modified_gmt":"2026-04-20T15:55:27","slug":"i-take-the-medicine-before-the-analysis-because-the-tablets-can-change-the-result","status":"publish","type":"post","link":"https:\/\/medilab.km.ua\/en\/i-take-the-medicine-before-the-analysis-because-the-tablets-can-change-the-result\/","title":{"rendered":"Taking medication before tests: when pills can change the result"},"content":{"rendered":"<p data-start=\"357\" data-end=\"745\">Preparation for laboratory tests is usually limited to the recommendation of an \u00abempty stomach\u00bb. However <strong data-start=\"450\" data-end=\"523\">one of the most underestimated factors is taking medications<\/strong>. Even an \u00abinnocent\u00bb tablet of paracetamol or vitamin C before donating blood can distort the results so much that the diagnosis will be made incorrectly. How to avoid such mistakes and what you need to know about medications before the tests?<\/p>\n<h2 data-start=\"747\" data-end=\"766\">Why is this important?<\/h2>\n<p data-start=\"768\" data-end=\"793\">Many drugs are able to:<\/p>\n<ul data-start=\"795\" data-end=\"1054\">\n<li data-start=\"795\" data-end=\"864\">\n<p data-start=\"797\" data-end=\"864\"><strong data-start=\"797\" data-end=\"827\">affect blood biochemistry<\/strong> (liver tests, sugar, cholesterol)<\/p>\n<\/li>\n<li data-start=\"865\" data-end=\"897\">\n<p data-start=\"867\" data-end=\"897\"><strong data-start=\"867\" data-end=\"897\">change hormonal background<\/strong><\/p>\n<\/li>\n<li data-start=\"898\" data-end=\"937\">\n<p data-start=\"900\" data-end=\"937\"><strong data-start=\"900\" data-end=\"937\">affect the cellular composition of the blood<\/strong><\/p>\n<\/li>\n<li data-start=\"938\" data-end=\"976\">\n<p data-start=\"940\" data-end=\"976\"><strong data-start=\"940\" data-end=\"976\">mask inflammation or infection<\/strong><\/p>\n<\/li>\n<li data-start=\"977\" data-end=\"1054\">\n<p data-start=\"979\" data-end=\"1054\"><strong data-start=\"979\" data-end=\"1054\">cause temporary adverse reactions that are reported in the laboratory report<\/strong><\/p>\n<\/li>\n<\/ul>\n<p data-start=\"1056\" data-end=\"1159\">The consequence is incorrect interpretation of the analysis, prescription of unnecessary treatment, or missed pathology.<\/p>\n<h2 data-start=\"1161\" data-end=\"1205\">What medications affect tests most often?<\/h2>\n<div class=\"_tableContainer_16hzy_1\">\n<div class=\"_tableWrapper_16hzy_14 group flex w-fit flex-col-reverse\">\n<table class=\"w-fit min-w-(--thread-content-width)\" data-start=\"1207\" data-end=\"2107\">\n<thead data-start=\"1207\" data-end=\"1260\">\n<tr data-start=\"1207\" data-end=\"1260\">\n<th data-start=\"1207\" data-end=\"1226\" data-col-size=\"md\">Group of drugs<\/th>\n<th data-start=\"1226\" data-end=\"1260\" data-col-size=\"md\">Potential impact on outcome<\/th>\n<\/tr>\n<\/thead>\n<tbody data-start=\"1314\" data-end=\"2107\">\n<tr data-start=\"1314\" data-end=\"1430\">\n<td data-start=\"1314\" data-end=\"1332\" data-col-size=\"md\"><strong data-start=\"1316\" data-end=\"1331\">Antibiotics<\/strong><\/td>\n<td data-start=\"1332\" data-end=\"1430\" data-col-size=\"md\">Increased liver enzyme levels, changes in intestinal microflora (affects stool and urine analysis)<\/td>\n<\/tr>\n<tr data-start=\"1431\" data-end=\"1516\">\n<td data-start=\"1431\" data-end=\"1468\" data-col-size=\"md\"><strong data-start=\"1433\" data-end=\"1467\">Hormones (including contraceptives)<\/strong><\/td>\n<td data-start=\"1468\" data-end=\"1516\" data-col-size=\"md\">Effect on TSH, LH levels, <a href=\"https:\/\/medilab.km.ua\/en\/analysis\/hormonal-panel\/diagnostics-of-reproductive-function\/prolactin-prolactin-prl\/\">prolactin<\/a>, glucose<\/td>\n<\/tr>\n<tr data-start=\"1517\" data-end=\"1610\">\n<td data-start=\"1517\" data-end=\"1549\" data-col-size=\"md\"><strong data-start=\"1519\" data-end=\"1548\">NSAIDs (ibuprofen, aspirin)<\/strong><\/td>\n<td data-start=\"1549\" data-end=\"1610\" data-col-size=\"md\">May suppress inflammatory markers, affect clotting<\/td>\n<\/tr>\n<tr data-start=\"1611\" data-end=\"1722\">\n<td data-start=\"1611\" data-end=\"1662\" data-col-size=\"md\"><strong data-start=\"1613\" data-end=\"1661\">Vitamins, especially fat-soluble ones (A, D, E, K)<\/strong><\/td>\n<td data-start=\"1662\" data-end=\"1722\" data-col-size=\"md\">May alter lipid, enzyme, and coagulation parameters<\/td>\n<\/tr>\n<tr data-start=\"1723\" data-end=\"1804\">\n<td data-start=\"1723\" data-end=\"1746\" data-col-size=\"md\"><strong data-start=\"1725\" data-end=\"1745\">Diuretics<\/strong><\/td>\n<td data-start=\"1746\" data-end=\"1804\" data-col-size=\"md\">Cause changes in electrolytes (sodium, potassium, calcium)<\/td>\n<\/tr>\n<tr data-start=\"1805\" data-end=\"1889\">\n<td data-start=\"1805\" data-end=\"1840\" data-col-size=\"md\"><strong data-start=\"1807\" data-end=\"1839\">Antidepressants, neuroleptics<\/strong><\/td>\n<td data-start=\"1840\" data-end=\"1889\" data-col-size=\"md\">Can affect <a href=\"https:\/\/medilab.km.ua\/en\/analysis\/biochemical-blood-tests\/carbohydrate-metabolism\/blood-glucose\/\">glucose level<\/a>, prolactin<\/td>\n<\/tr>\n<tr data-start=\"1890\" data-end=\"1994\">\n<td data-start=\"1890\" data-end=\"1913\" data-col-size=\"md\"><strong data-start=\"1892\" data-end=\"1912\">Iron preparations<\/strong><\/td>\n<td data-start=\"1913\" data-end=\"1994\" data-col-size=\"md\">May temporarily alter transferrin, ferritin, and serum iron levels<\/td>\n<\/tr>\n<tr data-start=\"1995\" data-end=\"2107\">\n<td data-start=\"1995\" data-end=\"2029\" data-col-size=\"md\"><strong data-start=\"1997\" data-end=\"2028\">Cytostatics, immunosuppressants<\/strong><\/td>\n<td data-start=\"2029\" data-end=\"2107\" data-col-size=\"md\">Affects the overall immune system, blood count, liver and kidney function<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div class=\"sticky end-(--thread-content-margin) h-0 self-end select-none\">\n<div class=\"absolute end-0 flex items-end\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n<h2 data-start=\"2109\" data-end=\"2152\">Do I need to stop taking the medication?<\/h2>\n<p data-start=\"2154\" data-end=\"2215\">Not always. <strong data-start=\"2165\" data-end=\"2206\">It is dangerous to discontinue medication on your own.<\/strong> Importantly:<\/p>\n<ol data-start=\"2217\" data-end=\"2546\">\n<li data-start=\"2217\" data-end=\"2291\">\n<p data-start=\"2220\" data-end=\"2291\">Notify the doctor or laboratory technician <strong data-start=\"2252\" data-end=\"2290\">a complete list of medications taken<\/strong>.<\/p>\n<\/li>\n<li data-start=\"2292\" data-end=\"2376\">\n<p data-start=\"2295\" data-end=\"2376\">To clarify, <strong data-start=\"2305\" data-end=\"2336\">What kind of analysis is prescribed?<\/strong> \u2014 not all tests are sensitive to medications.<\/p>\n<\/li>\n<li data-start=\"2377\" data-end=\"2459\">\n<p data-start=\"2380\" data-end=\"2459\">In some cases, the doctor recommends <strong data-start=\"2415\" data-end=\"2458\">take the test before taking the morning dose<\/strong>.<\/p>\n<\/li>\n<li data-start=\"2460\" data-end=\"2546\">\n<p data-start=\"2463\" data-end=\"2546\">If the analysis is planned <strong data-start=\"2486\" data-end=\"2525\">to monitor the effectiveness of treatment<\/strong>, the medication is not canceled.<\/p>\n<\/li>\n<\/ol>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9681\" src=\"https:\/\/medilab.km.ua\/wp-content\/themes\/woodmart\/images\/lazy.svg\" data-src=\"https:\/\/medilab.km.ua\/wp-content\/uploads\/2025\/05\/vrac-v-percatkah.jpg\" alt=\"The patient consults with the doctor before taking the test.\" width=\"1200\" height=\"900\" srcset=\"\" data-srcset=\"https:\/\/medilab.km.ua\/wp-content\/uploads\/2025\/05\/vrac-v-percatkah.jpg 1200w, https:\/\/medilab.km.ua\/wp-content\/uploads\/2025\/05\/vrac-v-percatkah-150x113.jpg 150w, https:\/\/medilab.km.ua\/wp-content\/uploads\/2025\/05\/vrac-v-percatkah-600x450.jpg 600w, https:\/\/medilab.km.ua\/wp-content\/uploads\/2025\/05\/vrac-v-percatkah-300x225.jpg 300w, https:\/\/medilab.km.ua\/wp-content\/uploads\/2025\/05\/vrac-v-percatkah-1024x768.jpg 1024w, https:\/\/medilab.km.ua\/wp-content\/uploads\/2025\/05\/vrac-v-percatkah-768x576.jpg 768w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><\/p>\n<h2 data-start=\"2548\" data-end=\"2568\">Special situations<\/h2>\n<ul data-start=\"2570\" data-end=\"3025\">\n<li data-start=\"2570\" data-end=\"2685\">\n<p data-start=\"2572\" data-end=\"2685\"><strong data-start=\"2572\" data-end=\"2615\">Thyroid hormones (thyroxine):<\/strong> TSH tests and <a href=\"https:\/\/medilab.km.ua\/en\/price\/?3325_search_1=%D0%A24&amp;3325_device=laptop&amp;3325_orderby=relevance&amp;3325_paged=1&amp;3325_filtered=true\">T4<\/a> better to give up <strong data-start=\"2650\" data-end=\"2674\">before the morning reception<\/strong> of the drug.<\/p>\n<\/li>\n<li data-start=\"2686\" data-end=\"2790\">\n<p data-start=\"2688\" data-end=\"2790\"><strong data-start=\"2688\" data-end=\"2710\">Insulin and glucose:<\/strong> testing is recommended for patients with diabetes <strong data-start=\"2755\" data-end=\"2789\">before insulin injection and before meals<\/strong>.<\/p>\n<\/li>\n<li data-start=\"2791\" data-end=\"2886\">\n<p data-start=\"2793\" data-end=\"2886\"><strong data-start=\"2793\" data-end=\"2823\">Anticoagulants (warfarin):<\/strong> may affect the coagulogram - the laboratory should be informed.<\/p>\n<\/li>\n<li data-start=\"2887\" data-end=\"3025\">\n<p data-start=\"2889\" data-end=\"3025\"><strong data-start=\"2889\" data-end=\"2918\">Antihistamines:<\/strong> may reduce the level of immune response - it is worth stopping taking it at least 48 hours before the allergen test.<\/p>\n<\/li>\n<\/ul>\n<h2 data-start=\"3027\" data-end=\"3069\">Why is it important to consult a doctor?<\/h2>\n<p data-start=\"3071\" data-end=\"3183\">The same drug may be critical for one test and have no effect on another. For example:<\/p>\n<ul data-start=\"3185\" data-end=\"3365\">\n<li data-start=\"3185\" data-end=\"3256\">\n<p data-start=\"3187\" data-end=\"3256\">Paracetamol changes <strong data-start=\"3206\" data-end=\"3229\">liver function tests<\/strong>, but <strong data-start=\"3235\" data-end=\"3249\">does not affect<\/strong> on TSH<\/p>\n<\/li>\n<li data-start=\"3257\" data-end=\"3365\">\n<p data-start=\"3259\" data-end=\"3365\">hormonal contraceptives can increase <strong data-start=\"3304\" data-end=\"3317\">prolactin<\/strong>, but <strong data-start=\"3323\" data-end=\"3339\">do not affect<\/strong> for a complete blood count<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"3367\" data-end=\"3508\">Proper communication with a doctor or biochemist allows you to determine, <strong data-start=\"3434\" data-end=\"3463\">What exactly needs correction?<\/strong> in the medication regimen before taking the test.<\/p>\n<h2 data-start=\"3510\" data-end=\"3553\">What to do if you can&#039;t cancel the medication?<\/h2>\n<p data-start=\"3555\" data-end=\"3577\">In this case, it is important:<\/p>\n<ul data-start=\"3579\" data-end=\"3768\">\n<li data-start=\"3579\" data-end=\"3638\">\n<p data-start=\"3581\" data-end=\"3638\"><strong data-start=\"3581\" data-end=\"3638\">indicate on the accompanying form which medications are being taken<\/strong><\/p>\n<\/li>\n<li data-start=\"3639\" data-end=\"3701\">\n<p data-start=\"3641\" data-end=\"3701\"><strong data-start=\"3641\" data-end=\"3682\">repeat the analysis under control conditions<\/strong> after consultation<\/p>\n<\/li>\n<li data-start=\"3702\" data-end=\"3768\">\n<p data-start=\"3704\" data-end=\"3768\"><strong data-start=\"3704\" data-end=\"3739\">evaluate results over time<\/strong>, and not in isolation<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"3770\" data-end=\"3891\">Even in complex cases, it is possible to adjust the diagnostic approach to obtain reliable and clinically meaningful data.<\/p>\n<p data-start=\"3893\" data-end=\"4099\">Taking medication before tests is not just a detail that can be omitted. It is the key to a correct diagnosis. In the laboratory, it is not only the blood that is important, but also the history of what has already entered the body before it is taken.<\/p>","protected":false},"excerpt":{"rendered":"<p>Preparation for laboratory tests is usually limited to the recommendation of an \u00abempty stomach\u00bb. However, one of the most underestimated factors is the intake of medications. Even<\/p>","protected":false},"author":627,"featured_media":9680,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-9679","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"_links":{"self":[{"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/posts\/9679","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/users\/627"}],"replies":[{"embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/comments?post=9679"}],"version-history":[{"count":0,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/posts\/9679\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/media\/9680"}],"wp:attachment":[{"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/media?parent=9679"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/categories?post=9679"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/tags?post=9679"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}