# What to Expect When Your Cat Needs a Blood Test Before Starting Steroids ## Key Takeaways - A pre-steroid blood test, typically including a Complete Blood Count (CBC) and biochemistry panel, establishes a critical health baseline for cats. This baseline assesses liver and kidney function, as these organs are primary sites for steroid metabolism and excretion, ensuring the drug's safety and efficacy. - Key values evaluated include liver enzymes (ALT, ALP) and kidney markers (BUN, creatinine), which indicate organ health and the cat's capacity to process corticosteroids. Abnormalities may necessitate dose adjustments, alternative medications, or delayed treatment initiation. - The blood test serves a dual purpose: to determine if steroids are safe for the individual cat and to provide a reference point for monitoring potential side effects during treatment. This proactive approach minimizes risks associated with immunosuppression and organ stress. - While the blood draw is a routine procedure causing minimal discomfort, certain clinical signs warrant immediate emergency veterinary attention, irrespective of steroid initiation. These include severe respiratory distress, collapse, inability to urinate, seizures, or repeated vomiting. - Owners should meticulously track specific parameters such as water intake, urination frequency and volume, appetite, and energy levels. This observational data, alongside bloodwork, aids the veterinarian in interpreting results and managing steroid therapy effectively. - Steroid treatment requires strict adherence to prescribed dosages and tapering schedules, as abrupt cessation can lead to dangerous withdrawal symptoms. Follow-up bloodwork is often necessary to monitor for iatrogenic effects on organ systems during long-term corticosteroid administration. --- If your veterinarian has recommended a blood test before your cat starts steroid medication, this is a standard safety step, not a sign that something is seriously wrong. Steroids, also called corticosteroids, are powerful drugs that reduce inflammation and calm an overactive immune system. They can help with conditions like allergies, asthma, inflammatory bowel disease, and certain skin problems. But because they affect many organs at once, your vet needs a clear picture of your cat's current health before writing that prescription. The blood test gives your vet a baseline. That means it shows what your cat's liver, kidneys, and other systems look like before any medication enters the body. This baseline serves two purposes. First, it helps your vet decide whether steroids are safe for your cat at all. Second, it gives a reference point so that if your cat has side effects later, your vet can compare new results to the old ones and see exactly what changed. Most cats tolerate steroids well, but the test is how your vet makes sure your cat is one of them. You do not need to prepare your cat for this test in any special way. Your vet may ask for a fasting sample, which means no food for about 8 to 12 hours beforehand, but many clinics do not require this for steroid screening. The blood draw itself takes only a few minutes. Your cat will feel a quick needle pinch, similar to a vaccination. Most cats go home the same day and act completely normal within an hour. ## Is This an Emergency? This situation is routine. A blood test before starting steroids is not an emergency, and neither is the steroid prescription itself. However, some signs in a cat should always send you to an emergency vet immediately, whether or not they relate to steroids. ```figure { "type": "triage", "title": "Urgency triage by severity of signs", "tiers": [ { "tier": "danger", "label": "Go to an emergency vet now", "signs": [ "Difficulty breathing, open-mouth breathing, or breathing with the belly heaving while at rest" ], "action": [ "Call ahead and go immediately", "Do not wait for a regular appointment" ] }, { "tier": "danger", "label": "Go to an emergency vet now", "signs": [ "Collapse, sudden weakness, or inability to stand" ], "action": [ "This can indicate a life-threatening problem", "Seek in-person emergency care right away" ] }, { "tier": "danger", "label": "Go to an emergency vet now", "signs": [ "Straining to urinate with little or no urine produced" ], "action": [ "This can mean a blocked bladder, which is fatal without urgent treatment" ] }, { "tier": "danger", "label": "Go to an emergency vet now", "signs": [ "Seizures or repeated vomiting" ], "action": [ "Both can signal serious underlying disease", "Do not wait to see if it passes" ] }, { "tier": "warn", "label": "Book a same-day appointment", "signs": [ "Increased thirst and urination that started suddenly, especially if your cat is drinking more than twice the usual amount" ], "action": [ "This can be a sign of kidney disease or diabetes", "Your vet needs to check before starting steroids" ] }, { "tier": "warn", "label": "Book a same-day appointment", "signs": [ "Vomiting more than once in 24 hours, or diarrhea lasting more than 24 hours" ], "action": [ "Dehydration can develop quickly in cats", "Same-day evaluation is appropriate" ] }, { "tier": "warn", "label": "Book a same-day appointment", "signs": [ "Yellow tint to the gums, skin, or whites of the eyes" ], "action": [ "This suggests liver problems", "Your vet should see your cat today" ] }, { "tier": "safe", "label": "Watch at home for 24 hours", "signs": [ "Mild lethargy or sleeping more than usual, with normal eating and drinking" ], "action": [ "If your cat is still eating, drinking, and using the litter box normally, you can monitor for one day", "If lethargy worsens, call your vet" ] }, { "tier": "safe", "label": "Watch at home for 24 hours", "signs": [ "A single episode of vomiting with no other signs" ], "action": [ "If your cat acts normal afterward and eats normally, you can watch for 24 hours", "More than one episode means call your vet" ] } ] } ``` | Urgency Level | Signs to Watch For | What to Do | |---|---|---| | Go to an emergency vet now | Difficulty breathing, open-mouth breathing, or breathing with the belly heaving while at rest | Call ahead and go immediately. Do not wait for a regular appointment. | | Go to an emergency vet now | Collapse, sudden weakness, or inability to stand | This can indicate a life-threatening problem. Seek in-person emergency care right away. | | Go to an emergency vet now | Straining to urinate with little or no urine produced | This can mean a blocked bladder, which is fatal without urgent treatment. | | Go to an emergency vet now | Seizures or repeated vomiting | Both can signal serious underlying disease. Do not wait to see if it passes. | | Book a same-day appointment | Increased thirst and urination that started suddenly, especially if your cat is drinking more than twice the usual amount | This can be a sign of kidney disease or diabetes. Your vet needs to check before starting steroids. | | Book a same-day appointment | Vomiting more than once in 24 hours, or diarrhea lasting more than 24 hours | Dehydration can develop quickly in cats. Same-day evaluation is appropriate. | | Book a same-day appointment | Yellow tint to the gums, skin, or whites of the eyes | This suggests liver problems. Your vet should see your cat today. | | Watch at home for 24 hours | Mild lethargy or sleeping more than usual, with normal eating and drinking | If your cat is still eating, drinking, and using the litter box normally, you can monitor for one day. If lethargy worsens, call your vet. | | Watch at home for 24 hours | A single episode of vomiting with no other signs | If your cat acts normal afterward and eats normally, you can watch for 24 hours. More than one episode means call your vet. | If you are ever unsure, call your veterinary clinic. They know your cat's history and can tell you whether a sign needs urgent attention. ## Why Your Vet Wants Bloodwork Before Steroids Steroids work by suppressing inflammation throughout the body. That is why they help so many different conditions. But that same widespread effect means they can influence organs that are not the target of treatment. The liver and kidneys are especially important because steroids are processed and cleared through those organs. The blood test your vet orders is usually a complete blood count and a biochemistry panel. A complete blood count, or CBC, measures red blood cells, white blood cells, and platelets. A biochemistry panel measures chemicals in the blood that reflect organ function. Together, these tests give your vet a broad view of your cat's internal health. The most important values for steroid safety are liver enzymes and kidney values. Liver enzymes are proteins that help the liver do its work. When liver cells are damaged, these enzymes leak into the blood, and the levels rise. Kidney values, specifically blood urea nitrogen and creatinine, rise when the kidneys are not filtering waste properly. If any of these numbers are abnormal, your vet may delay the steroid prescription, adjust the dose, or choose a different medication entirely. ## What the Results Tell Your Vet Normal results mean your vet can proceed with confidence. The steroid dose will be based on your cat's weight and the condition being treated. Dosing must come from your treating veterinarian, because the right amount depends on the specific drug, the disease, and your cat's individual response. Never adjust or repeat a steroid dose on your own. Mildly abnormal results do not automatically mean your cat cannot have steroids. Sometimes the abnormality is minor and unrelated to the condition being treated. Your vet may repeat the test, run additional tests, or choose a steroid that is shorter-acting and easier on the liver. The goal is always to find the safest way to treat your cat's actual problem. Significantly abnormal results may mean steroids are too risky. In that case, your vet will discuss alternative treatments. There are many options, and your vet will explain which ones fit your cat's specific diagnosis. The blood test is not a barrier to treatment. It is a tool that helps your vet choose the treatment most likely to help without causing harm. ## What Else Could Be Going On The signs that led your vet to consider steroids, such as itching, vomiting, diarrhea, or coughing, can have several causes. A blood test helps narrow those down. For example, increased thirst and urination can be caused by kidney disease, diabetes, or a hormone imbalance, and each of those needs a different treatment than steroids. In some cases, the blood test reveals a condition that was not suspected. Cats are skilled at hiding illness, and routine bloodwork sometimes catches early kidney disease or liver problems before they cause visible signs. Finding these issues before starting steroids is exactly why the test is recommended. It protects your cat from a medication that could make an undiagnosed condition worse. The US Food and Drug Administration provides guidance on giving pet medication safely, including the importance of following your veterinarian's instructions exactly. Your vet will also explain what side effects to watch for once your cat starts steroids, such as increased thirst, increased appetite, or changes in urination. Knowing these in advance helps you tell the difference between a normal adjustment and a problem that needs attention. ## What Happens Next After the blood test, your vet will usually have results within a day or two. Some clinics run the tests in-house and give you results the same day. Others send samples to an outside laboratory, which takes longer. Your vet will call you with the results and the treatment plan. If your cat is cleared for steroids, you will receive specific instructions on how to give the medication. Follow those instructions exactly. Giving too much, too little, or stopping suddenly can cause problems. The American Veterinary Medical Association offers resources on working with your veterinarian to keep your pet healthy, and your vet's team is always your first source for questions. The blood test is a short, simple step that makes the entire course of treatment safer. It takes minutes, causes minimal discomfort, and gives your vet the information needed to protect your cat. Most owners find that the peace of mind is worth the small amount of stress. ## What You Can Do at Home Right Now If your cat is stable, eating, drinking, and behaving normally, there is no need for urgent action. The blood test your vet recommended is a routine safety step, not a sign that something is actively wrong. Your job at home is simple: keep your cat comfortable, keep their routine steady, and gather a few pieces of information that will help your vet interpret the results. Do not start any steroid medication you may already have at home. Do not give a leftover course of prednisolone from a previous illness. Steroids change how the liver, kidneys, and immune system behave, and giving them before your vet has a baseline can mask problems or make them worse. The US Food and Drug Administration warns that giving pet medication without clear instructions is a common source of dosing errors and side effects. Your vet must determine the dose and the schedule for your specific cat. You also should not stop a steroid your cat is already taking. If your cat has been on steroids and your vet now wants bloodwork, stopping suddenly can cause a dangerous withdrawal reaction. Keep giving the medication exactly as prescribed and let your vet guide any change. ## What to Write Down Before You Call A few minutes of observation at home can make the veterinary visit more productive. Write down what you see in plain words, with dates and times. Track how much your cat drinks. Fill a water bowl to a set level each morning and note how much is gone by evening. A cat that suddenly empties a large bowl every day is drinking more than normal, and that matters for kidney and diabetes screening. Track urination. Note how often your cat uses the litter box and whether the clumps are larger than usual. If your cat is straining to urinate and producing little or nothing, that is an emergency. Do not wait for a blood test. Seek in-person emergency care immediately. Track appetite and weight. A kitchen scale can weigh a cat, but only if the cat stays still. Weigh your cat at the same time each day for three days and take the average. A change of more than half a pound in a week is worth reporting. Track energy and behavior. Note if your cat is sleeping more, hiding, or reluctant to jump onto furniture. Also note vomiting, diarrhea, or changes in stool color. ## The Test List and Why Each Item Matters Your vet will likely recommend a small panel of tests. Here is what each one checks and why it matters before steroids. | Test | What It Checks | Why It Matters Before Steroids | |------|----------------|-------------------------------| | Complete blood count (CBC) | Red cells, white cells, platelets | Steroids can raise white cell counts and hide infection. A baseline tells your vet what is normal for your cat. | | Blood chemistry panel | Liver enzymes, kidney values, protein, glucose | Steroids stress the liver and can raise blood sugar. Baseline values show whether your cat can handle the drug. | | Kidney values (BUN and creatinine) | How well the kidneys filter waste | Steroids increase thirst and urine output. If kidneys are already weak, steroids can worsen that. | | Liver enzymes (ALT and ALP) | Liver cell health and bile flow | Steroids can elevate these values. A high baseline may mean the liver needs attention first. | | Urinalysis | Urine concentration, protein, glucose, infection | Pairs with kidney bloodwork. Dilute urine or glucose in urine can change the treatment plan. | | Thyroid test (in older cats) | Thyroid hormone level | Overactive thyroid can mimic steroid side effects. Your vet may want this before long-term steroids. | This list is typical, not fixed. Your vet may add or skip tests based on your cat's age, breed, and symptoms. The goal is a clear picture of your cat's health before you introduce a drug that affects many body systems. The American Veterinary Medical Association advises pet owners to ask their vet why each test is recommended and what the results will change. ## What a Veterinary Visit Usually Involves The visit starts with a history. Your vet will ask about appetite, thirst, urination, vomiting, diarrhea, weight change, and energy. They will also ask about any other medications, including flea and tick products, supplements, and prescription diets. Then comes the physical exam. Your vet will feel your cat's abdomen to check kidney size and bladder fullness. They will listen to the heart and lungs. They will check gum color and moisture, feel lymph nodes, and look at the skin and coat. These hands-on steps cannot be done remotely. They are essential because steroids can affect the heart, kidneys, and immune system. Blood is drawn from a leg vein. Most cats tolerate this with minimal restraint. The sample is run in the clinic or sent to a laboratory. Results may take 15 minutes or up to two days, depending on the clinic. Cost varies widely by region and clinic. A basic pre-steroid blood panel typically falls in the range of $100 to $250. Adding a urinalysis and thyroid test can bring the total to $200 to $400. These are general ranges, not quotes. Your clinic can give you an exact estimate before testing. What drives cost up: same-day results, full thyroid panels, and repeat testing for monitoring. What drives cost down: bundled preventive care packages and clinics that run tests in-house. ## When an Online Vet Can Help, and When It Cannot This topic requires hands-on care. The blood test itself must happen in person. The physical exam that goes with it must happen in person. If your cat is straining to urinate, collapsed, vomiting repeatedly, or breathing with effort, do not use a remote service. Those are emergencies that need immediate in-person care. A remote consultation is genuinely useful in specific situations. If your cat has a mild, known condition and you are wondering whether a new sign warrants a visit, an online vet can help you decide. If your cat is already on steroids and you have a question about a side effect like increased thirst, a remote vet can advise. If you are managing a chronic condition like inflammatory bowel disease and need a recheck on progress, a video call can work well. A remote vet can take a history, watch your cat move on video, look at visible signs like skin lesions or eye discharge, and give advice. In many states, a veterinarian can prescribe after a remote consultation. But prescribing rules differ by state, and many vets will require an in-person examination first, especially for a drug like a steroid that needs monitoring. A remote vet cannot palpate the abdomen, listen to the chest, take a temperature, run bloodwork, or image anything. Those limitations matter here because the whole point of the blood test is to gather data that only a physical sample can provide. Use remote care for questions and triage. Use in-person care for the test itself. ## Common Mistakes Owners Make Before and During Steroid Treatment The most common mistake is stopping the medication abruptly once the cat seems better. Steroids affect many body systems, and stopping suddenly can cause a dangerous drop in blood pressure, weakness, or a return of the original illness with more force. Always follow the tapering schedule your veterinarian provides. Tapering means gradually reducing the dose over days or weeks so the body can adjust. Another frequent error is giving the medication with food one day and on an empty stomach the next. Some steroids absorb differently depending on food. Consistency matters. Ask your vet whether to give the pill with a meal or between meals, then do it the same way every time. Owners also sometimes double a missed dose to catch up. That can cause side effects. If you miss a dose, give it as soon as you remember, unless the next dose is close. In that case, skip the missed one and continue the normal schedule. When in doubt, call your clinic. A fourth mistake is assuming the bloodwork is a one-time event. Your vet may want repeat blood tests during treatment to check liver and kidney function while the cat is on the medication. These follow-up tests catch problems early, when they are easier to manage. | Common Mistake | Better Action | | --- | --- | | Stopping steroids suddenly | Follow the vet's tapering plan exactly | | Giving doses at different times or with different foods | Keep a consistent routine for timing and food | | Doubling a missed dose | Skip it if the next dose is near, or call the clinic | | Skipping follow-up bloodwork | Keep the scheduled rechecks to monitor organ health | ## How to Reduce the Chance of Problems Recurring Keep a simple medication log. Write down the date, the dose, and any changes you notice in appetite, thirst, urination, or energy. Bring this log to every appointment. It gives your vet concrete information that bloodwork alone cannot show. Store the medication exactly as directed. Some steroids need refrigeration, others do not. Read the label and ask the pharmacy if you are unsure. Keep pills in the original container, out of reach of children and pets. Never give leftover steroids from a previous illness. The dose and the drug may be wrong for the current problem. The [FDA's guidance on safe use of pet medications](https://www.fda.gov/animal-veterinary/animal-health-literacy/how-give-your-pet-medicine-safely) explains why using the right drug, dose, and schedule matters for safety. Watch for signs that need a call to your vet: vomiting, diarrhea, increased thirst that seems extreme, or a cat that stops eating for more than a day. These do not always mean an emergency, but they deserve a phone call. If your cat collapses, has a seizure, or struggles to breathe, seek emergency care immediately. ## What Recovery and Ongoing Management Usually Look Like Recovery depends on the condition being treated. For allergic skin disease, you may see improvement in itching within a few days. For inflammatory bowel disease, appetite and stool quality may improve over one to two weeks. For immune-mediated conditions, improvement can take several weeks. Steroid treatment is often not permanent. Many cats finish a course and return to normal. Others need a low maintenance dose for months or years. Your vet will aim for the lowest dose that controls the disease, because lower doses mean fewer side effects. During treatment, you may notice your cat drinks more and urinates more. This is common and usually reversible when the dose is reduced or stopped. Weight gain and a dull coat can also occur. Report these to your vet at rechecks, but do not stop the medication on your own. The [American Veterinary Medical Association's pet owner resources](https://www.avma.org/resources-tools/pet-owners) describe how regular communication with your veterinarian supports safe long-term treatment. Most cats tolerate steroids well when the dose is managed carefully and bloodwork is repeated as scheduled. ## Frequently Asked Questions **How long will my cat need to be on steroids?** It depends on the illness. Some cats take steroids for one to two weeks. Others need a low dose for months or years. Your vet will reassess at each visit and adjust the dose based on how the cat responds and how the bloodwork looks. Do not assume the first prescription is the final plan. Many cats eventually taper off completely, especially if the underlying condition resolves or is controlled by other medications. **Can I give my cat a steroid from my own medicine cabinet?** No. Human steroids are different drugs with different strengths and risks. Giving a human medication to a cat can cause serious harm, including liver damage or stomach ulcers. The [FDA's guidance on giving pet medication safely](https://www.fda.gov/animal-veterinary/animal-health-literacy/how-give-your-pet-medicine-safely) stresses that pets should only receive drugs prescribed for them by a veterinarian. The dose must be calculated for your cat's weight and condition. **What if my cat spits out the pill?** Check the floor and the cat's mouth before assuming the dose was swallowed. If you are unsure, do not give another pill. Giving a double dose is more dangerous than missing one. Call your clinic for advice. Some pharmacies can compound the steroid into a flavored liquid or a small transdermal gel that goes on the ear. Ask your vet if that option fits your cat. **Will the blood test hurt my cat?** The blood draw takes a few seconds and feels like a quick pinch. Most cats tolerate it well, especially with gentle handling. Some clinics use a tiny numbing spray on the skin first. Afterward, your cat may be sleepy for a few hours. A small bruise at the site is possible but rare. Serious complications from a routine blood draw are very uncommon. **How often will bloodwork need to be repeated?** Many vets recommend a recheck two to four weeks after starting steroids, then every three to six months during long-term treatment. The schedule depends on the dose and the disease. If your cat is on a short course, one follow-up test may be enough. If the dose is high or the treatment is long, more frequent checks protect the liver and kidneys. **What signs mean I should call the vet right away?** Call if your cat vomits repeatedly, has diarrhea for more than a day, stops eating for 24 hours, or seems unusually weak. Extreme thirst that leads to constant drinking and large urine volumes also warrants a call. If your cat collapses, has a seizure, or cannot breathe normally, go to an emergency clinic immediately. These signs can indicate a serious reaction and should not wait for a regular appointment. ## Related Clinical & Scientific Guides * [What Are the Side Effects of Bravecto for Dogs? What to Watch For](/knowledge/veterinary-medicine/pet-medication-guide/bravecto-side-effects-dogs) * [Can You Give Your Dog Human Allergy Medicine? Whats Safe](/knowledge/veterinary-medicine/pet-medication-guide/dog-human-allergy-medicine-safe) * [Can You Give Your Dog Dramamine for Car Sickness?](/knowledge/veterinary-medicine/pet-medication-guide/dog-dramamine-car-sickness) ## References and Further Reading - [FDA Center for Veterinary Medicine Animal Drug Information](https://www.fda.gov/animal-veterinary) - [FDA Safe Use of Pet Medications](https://www.fda.gov/animal-veterinary/animal-health-literacy/how-give-your-pet-medicine-safely) - [AVMA Pet Owner Resources](https://www.avma.org/resources-tools/pet-owners) - [MSD Veterinary Manual Pet Owner Version](https://www.msdvetmanual.com/pet-owners) - [AAHA Pet Owner Resources](https://www.aaha.org/for-pet-parents/) ## Related Articles - [What to Expect When Your Cat Needs a Urine Test Before Getting Medication](/knowledge/veterinary-medicine/pet-medication-guide/cat-urine-test-before-medication) - [What to Expect When Your Dog Needs a Blood Test Before Starting Pain Medication](/knowledge/veterinary-medicine/pet-medication-guide/dog-blood-test-before-pain-medication) - [What to Expect When Your Cat Needs a Thyroid Medication Adjustment](/knowledge/veterinary-medicine/pet-medication-guide/cat-thyroid-medication-adjustment) - [What to Expect When Your Dog Needs a Urine Test Before Starting Seizure Medication](/knowledge/veterinary-medicine/pet-medication-guide/dog-urine-test-before-seizure-medication) - [What to Expect When Your Dog Needs a Fecal Test Before Deworming](/knowledge/veterinary-medicine/pet-medication-guide/dog-fecal-test-before-deworming) > This article is general educational information for pet owners. It is not a substitute for veterinary diagnosis, examination, or treatment. If your pet is showing severe or rapidly worsening signs, contact an emergency veterinary hospital immediately.