Needles can be scary. Worrying about your pet’s bloodwork can be even scarier… But blood tests don’t have to be so frightening. Whether your pet requires tests for an upcoming procedure, or whether he or she has been ill and your vet recommends bloodwork, you’re bound to have questions as any concerned pet owner would. What does each test measure? What if the numbers are outside the reference range? Wouldn’t it be nice to know how to interpret your dog or cat’s labwork results? The Meowing Vet is here to help! So get comfy by changing into your yoga pants and pouring yourself a nice hot cup of tea, ’cause this post is loooooooong, girl!
The CBC, or Complete Blood Count, is typically the first thing you’ll see on your pet’s bloodwork report. This group of tests analyzes blood cells (red blood cells, white blood cells, and platelets) as well as blood proteins.
- RBC: RBC is the measurement of the number of red blood cells (or erythrocytes) per given volume of blood. Red blood cells carry oxygen and nutrients to be used by each tissue in the body as well as transport waste products away from these tissues for elmination. A low RBC count is defined as anemia. Sometimes, RBC count can be high (i.e. erythrocytosis) if your pet was excited or nervous during its blood draw; adrenaline kicks in during nervousness, telling the spleen to release a bunch of red blood cells to prepare for “fight-or-flight” mode.
- HGB: Hemoglobin is a protein that binds iron to red blood cells to facilitate oxygen transport. A low HGB means that the body’s organs may not be receiving as much oxygen as normal.
- TIBC: Total Iron Binding Capacity measures how much of the protein that can carry iron to the rest of the body is present in blood. Low TIBC may be an indication of anemia, malnutrition, liver disease, or inflammation. High TIBC can occur with iron deficiency.
- HCT / PCV: Hematocrit (HCT) and Packed Cell Volume (PCV) both indicate what percentage of blood is comprised of red blood cells (as opposed to other types of blood cells, blood proteins, and water). A normal measurement in a dog is about 45%, while normal in a cat is around 35%. HCT is calculated by the laboratory machine that analyzes the test tubes containing a blood sample. Due to potential errors in the machine, HCT is not as accurate as PCV, which is measured visually by your vet or laboratory technician. PCV eliminates machine error. Just like a low RBC count, a low HCT or PCV also indicates anemia. A high HCT or PCV can indicate excitement (as previously explained) or dehydration. If your pet is dehydrated, the same volume of blood will have less water content, causing red blood cells to make up a higher proportion of that same blood volume, creating a higher HCT or PCV than if your pet was well hydrated.
- MCV: Mean Corpuscular Volume measures the average size of red blood cells. Normally-sized red blood cells are termed normocytic while red blood cells that are too large or too small are called macrocytic and microcytic, respectively. Although healthy animals are typically normocytic, normally-sized red blood cells may also be observed in certain chronic illnesses (such as kidney failure or certain cancers). Large red blood cells may be seen in cases of anemia; in the face of low red blood cells, bone marrow, which makes red blood cells, is triggered to prematurely release immature red blood cells (or reticulocytes, which are larger than the mature red blood cells typically released into the bloodstream in normal patients). Large red blood cells may also be seen in certain diseases (such as feline leukemia virus infection), certain vitamin or mineral deficiencies, or may be a normal finding in some poodles. Small red blood cells may be observed with other mineral deficiencies (low iron or copper), liver diseases (such as portosystemic shunts), or can be a normal finding in young animals and some dog breeds (such as Akitas and Shiba Inus).
- MCH / MCHC: Mean Corpuscular Hemoglobin and Mean Corpuscular Hemoglobin Concentration (the latter being more accurate and more useful) measure how much hemoglobin is attached to red blood cells, generally described as the “color” of red blood cells. Normally pigmented red blood cells (i.e. those with normal MCHC) are normochromic and carry an appropriate amount of hemoglobin. Pale red blood cells (those with low MCHC) are hypochromic and can be seen with iron deficiency (since hemoglobin is made up of iron) or immature red blood cells in the bloodstream (known as polychromasia). Red blood cells that have been destroyed in the bloodstream (by a process known as hemolysis) due to certain infections, toxins, or auto-immune diseases can appear “darker” than normal (or hyperchromic), resulting in a high MCHC.
- RDW: Red Cell Distribution Width measures the degree of size variation among red blood cells (known as anisocytosis) and is related to MCV.
- nRBC: Nucleated red blood cells (or metarubricytes) are not normally observed in the bloodstream; instead, these types of red cells hang out in the bone marrow. However, in certain states of anemia, bone marrow injury (brought on by toxins, heat stroke, cancer, inflammation, or infection), recent bone fracture or surgery, or damage to the spleen, nucleated red blood cells may be seen in circulation in the bloodstream. Additionally, nRBC may be falsely elevated if the blood machine misidentifies white blood cells for nucleated red blood cells.
- Reticulocyte # / %: Reticulocytes are immature red blood cells. As explained above, to compensate for decreased mature red blood cells in the bloodstream in cases of anemia, the bone marrow releases immature red blood cells until the cause of the anemia resolves. The degree of how many immature red blood cells are released indicates how well your pet’s bone marrow is working to regenerate red blood cells. In the face of anemia, a low reticulocyte count (either indicated by a number or a percentage of total red blood cells) means that the bone marrow is not regenerating well, while a high reticulocyte count means that the bone marrow is functioning well to produce new red blood cells when old ones are lost.
- Poikilocytes / Red Blood Cell Inclusions: In addition to analyzing your pet’s blood via machine, your vet or laboratory technician may often look directly at a blood smear under a microscope to visually assess the character of blood cells for higher accuracy. The observance of potential poikilocytes (abnormal red blood cell shapes such as acanthocytes, echinocytes, schistocytes, spherocytes, or target cells) or inclusions (abnormal findings inside red blood cells such as Heinz bodies or Howell-Jolly bodies) will aid your vet in narrowing down where your pet’s illness lies. Additional uses of a direct blood smear include searching for infectious disease agents inside red blood cells, such as if Mycoplasmosis were suspected in your cat.
- WBC: WBC is the measurement of the number of white blood cells (or leukocytes) per given volume of blood. White blood cells march to the forefront of inflammation to help combat infections and foreign material detected in the body (for instance, a splinter of wood in your hand). The two main categories of white blood cells are mononuclear cells (including monocytes and lymphocytes) and granulocytes (which include neutrophils, eosinophils, and basophils). A high WBC count (i.e. leukocytosis) indicates inflammation or infection. A low white blood cell count (i.e. leukopenia) can occur with sudden, severe inflammation or infection when white blood cells rush out of the bloodstream to the tissue site of disease. Decreased production of white blood cells can also be the result of bone marrow disorders, certain infections (such as canine parvovirus, canine distemper, infectious canine hepatitis, canine Ehrlichiosis, or feline panleukopenia), or toxicity (estrogen, chemotherapy or immunosuppressive drugs). A respective increase or decrease in any of the following types of white blood cells can cause a leukocytosis or leukopenia. Your vet may also wish to analyze a direct blood smear if he or she is suspicious of different infectious diseases (such as tick-borne diseases, such as Rickettsial organisms) as the infectious agent may be observed inside a white blood cell.
- Segmented Neutrophils (Seg): Segmented neutrophils are mature neutrophils, the predominate white blood cell type in dogs and cats. Segmented neutrophils increase during infectious or inflammatory states or during episodes of excitement (if your pet is anxious during its blood draw, see above for high RBC count) or periods of stress or high cortisol levels (as in the case of ill pets, pets currently taking prednisone, or dogs with Cushing’s disease in which too much of the stress hormone cortisol is produced). Cushing’s polar opposite, Addison’s disease (in which the body fails to make appropriate stress hormones), may be suspected if your pet is ill yet his or her segmented neutrophil count is normal. Remember, most ill animals are in a state of bodily stress and are thereby expected to have a high segmented neutrophil count, known as a stress leukogram; this response does not occur with Addison’s disease.
- Band Neutrophils (Band): Band neutrophils are immature neutrophils, and a high presence of these bad boys in the bloodstream (known as a left shift) indicates pretty darn awful inflammation or infection. During a left shift, your vet may also detect toxic changes to neutrophils; the severity of these toxic changes correlates to the severity of inflammation or infection.
- Lymphocytes (Lymph): The white blood cells known as lymphocytes (which include T cells and B cells) may reside both in the bloodstream and lymph system. Increased numbers of lymphocytes may occur due to excitement, chronic inflammatory conditions or infections, Addison’s disease, and certain cancers (leukemia, lymphoma). Young animals also have a normally higher number of lymphocytes than adult animals. Causes of decreased bloodstream lymphocytes include sudden or overwhelming inflammation, stress, disorders of lymph or lymphatic circulation, and decreased production (due to lymphoma, Histoplasmosis fungal infection, or immunuosuppressive chemotherapy drugs).
- Monocytes (Mono): Monocytes are a type of white blood cell that travel in the bloodstream only a short time to reach maturity before they can do their thing by travelling into tissue (where they are then termed macrophages and help protect and clean up waste from tissues). They may be increased during periods of inflammation or infection.
- Eosinophils (Eos): Eosinophils are white blood cells that are stimulated during hypersensitivity reactions (allergies, asthma, insect bites or stings, etc.), parasitic infections (such as heartworm disease), and certain types of cancers (such as mast cell tumors and lymphoma); eosinophil count will increase in these disease states. Conversely, eosinophil counts are often low during periods of inflammation or stress (i.e. stress leukogram).
- Basophils (Baso): Basophils, another type of white blood cell, can oftentimes be thought of as the stereotypical ignored middle child of the bloodstream (sorry, all you middle child readers out there *Marcia, Marcia, Marcia!*). An increased basophil count typically occurs in conditions that also trigger a high eosinophil count. A low basophil count is not a significant finding.
- Platelet Count Advia (Plt): Platelets are tiny broken-off pieces of megakaryocytes, “Mama Platelet” cells created by bone marrow. Platelets (or thrombocytes) function in concert with clotting factor proteins to aid in blood clotting (i.e. the reason your puppy doesn’t bleed out when your grumpy cat swats him across his inquisitive face). A high platelet count (or thrombocytosis) can occur during excitement, secondary to chronic inflammation or bleeding, following a splenectomy, due to steroid use, or rarely due to cancer. Low platelets (or thrombocytopenia) is more worrisome and can occur following decreased production secondary to bone marrow disorders, platelet destruction due to immune-mediated disease (which can be auto-immune or secondary to certain medication use, infections, or cancer), hemorrhage, blood clots, or disorders of the spleen. However, some dog breeds may have a low platelet count to no concern, such as Cavalier King Charles spaniels and greyhounds. Related platelet tests include MPV (Mean Platelet Volume), PDW (Platelet Distribution Width), and Platelet Morphology. Even if your pet has a normal platelet number, your vet may order additional tests if he or she is concerned about poor platelet function (or thrombopathia).
- Plasma Appearance / Plasma Protein: Plasma is the liquid portion of a blood sample after the test tube has been spun in a centrifuge to separate out the blood cells from the plasma. Plasma contains both clotting factor proteins and serum (which includes liquid, electrolytes, glucose, carbon dioxide, and other proteins not involved in blood clotting). The color of plasma is important in assessing disease processes. Normally, plasma is a transparent pale yellow. Pink or red plasma indicates red blood cell destruction (hemolysis); bright orange plasma can occur with increased bloodstream bilirubin due to liver or gall bladder disease or hemolysis; and cloudy white plasma contains a higher than usual triglyceride or fat content (as can occur in patients following a meal or with diabetes mellitus, Cushing’s disease, or hypothyroidism). Plasma protein may be increased due to dehydration (resulting in less water content, thus a greater proportion of protein per same unit volume) or inflammation. Alternatively, a low plasma protein level can occur due to protein loss (via bleeding, loss from the GI tract or kidneys, or leakage from large skin wounds) or can occur due to water-retentive states (such as receiving too much IV fluids, congestive heart failure, or liver failure). Specific plasma proteins such as Albumin and Globulins are further analyzed in the Chemistry portion of blood testing.
Once the laboratory machine has completed measuring the CBC and the blood sample has coagulated, the serum is then separated off the plasma for Chemistry analyzing.
- Glucose (Glu): Glucose is commonly referred to as “blood sugar.” Glucose is both acquired from food via absorption by the intestines as well as produced by the body (primarily by the liver by converting amino acids and fat into glucose in times of need). Different machines feature slightly different reference ranges (or normal values) for blood glucose in dogs and cats, but typical reference ranges are 60-120 mg/dL for dogs and 70-130 mg/dL for cats. Low glucose levels (or hypoglycemia) can occur secondary to starvation, extreme exercise (ex. hunting dogs), skipped meals in very young animals or toy/miniature dog breeds, Addison’s disease, liver failure, sepsis, and certain tumors and cancers (ex. insulinomas). High blood glucose (or hyperglycemia) may be transiently caused secondary to food ingestion or due to stress, pancreatitis, Cushing’s disease, hyperthyroidism, or steroid administration. Consistently high blood glucose readings is highly suggestive of diabetes mellitus.
- BUN: Blood urea nitrogen is the measurement of how much urea is in the bloodstream. Urea is a waste product of ingested protein that is processed by the liver to be then transported through the bloodstream to the kidneys for excretion in urine. (One of the many functions of the kidneys is to remove toxic waste products from the body.) Because the metabolism of BUN involves the gastrointestinal tract, liver, and kidneys, dysfunction of any of these systems can result in an altered BUN measurement on bloodwork. High BUN can be the result of dehydration, fever, a high protein diet, kidney failure, or GI bleeding (such as gastric ulcers). Since the liver helps make BUN, liver disease (liver failure, portosystemic shunts) can result in decreased BUN. BUN’s “bloodwork cousin,” Creatinine, is a more specific measurement of kidney function.
- Creatinine: Because it does not involve the intestines or liver, creatinine is a more accurate depiction of renal function than is BUN. Dehydration can also cause elevated creatinine, but this measurement is not affected by GI bleeding (unlike BUN). Creatinine is a waste product produced by muscles, which is taken up by the bloodstream to then be carried to the kidneys to be eliminated in urine. If the kidneys are not doing their job of filtering waste products out of the bloodstream, then creatinine can build-up, resulting in an elevated level on bloodwork. Not only do patients with renal dysfunction have a high creatinine level, but some healthy patients may have a normally higher creatinine than other patients, such as heavily muscled dog breeds such as greyhounds and pit bulls.
- Calcium (Ca): Calcium is not only a building-block to strong bones; it also aids in muscle contraction, electrical conduction in nerves, hormone activity, and blood clotting. Decreased calcium concentrations can cause decreased muscle and nerve activity, including decreased heart muscle action. Causes of low calcium include low albumin (this blood protein binds to calcium, so when it is diminished, it can also decrease total calcium), disorders of the parathyroid gland (primary hypoparathyroidism or secondary nutritional hyperparathyroidism), vitamin D deficiency, pregnancy eclampsia, furosemide (Lasix®) use, ethylene glycol (antifreeze) toxicity, pancreatic disease (pancreatitis, exocrine pancreatic insufficiency), and acute kidney failure. Certain laboratory errors may also result in a falsely low calcium measurement, such as certain blood tube collections. Conversely, high calcium levels can cause unregulated activity of the muscular and nervous systems as well as the formation of mineral deposits (of bound calcium and phosphorous) in the muscles, heart, lungs, and kidneys, which in turn can trigger cardiac arrhythmias (abnormal heartbeats) and secondary kidney failure. Causes of high calcium include pituitary gland disease (primary hyperparathyroidism), high vitamin D levels (from ingesting certain rat poisons or from uncommon fungal infections), renal failure, Addison’s disease, some bone diseases, and certain cancers (due to the creation of a product known as PTHrp). (If your vet is suspicious of parathyroid disease or a PTHrp-secreting tumor, a specific calcium test called ionized calcium may be ordered.) Moreover, puppies under 6 months old normally have higher calcium levels than adult dogs (this does not occur in kittens).
- Phosphorous (P): Along with calcium, phosphorus also promotes healthy bone development as well as plays a vital role in cellular energy function. Young puppies and kittens will have a normally elevated phosphorus level. Other causes of high phosphorus include renal dysfunction, hyperthyroidism, parathyroid gland disease (hypoparathyroidism), excess vitamin D, and certain bone and muscle diseases. As discussed under Calcium, high calcium and phosphorus levels can cause the development of mineral deposits throughout the body (particularly when the values of calcium X phosphorus in mg/dL exceed 70). On the other hand, low phosphorus can be the result of other parathyroid disease (hyperparathyroidism), certain kidney diseases (ex. Fanconi syndrome), high insulin levels, pregnancy eclampsia, and certain PTHrp-producing cancers.
- Total Protein (TP): The same causes for Plasma Protein changes as discussed under the CBC section above can cause alterations in Total Protein on Chemistry. To investigate further, analyzing Albumin and Globulins, two individual protein categories that make up Total Protein, is in order.
- Albumin (Alb): Albumin can be increased with dehydration. However, low albumin is more concerning. Albumin is a highly important protein produced by the liver that acts as a “taxi cab” to transport essential substances throughout the body (such as bilirubin and fatty acids). Additionally, albumin helps maintain oncotic pressure in the bloodstream. This means that it’s kinda like a magnet by attracting water to stay with it inside blood vessels instead of leaking out into body tissues or cavities. If albumin becomes too low (under 1.5 g/dL is scary!), there is not enough attractive pull to keep water in the bloodstream, so it disperses outwards to cause tissue edema (such as in the limbs), ascites (fluid in the abdominal cavity), or pulmonary edema and pleural effusion (fluid inside or surrounding the lungs, which can be life-threatening). Causes of low albumin include decreased production (due to malnutrition, inflammation, and liver disease) or increased loss from the body (via the kidneys, GI tract, or large skin wounds).
- Globulins (Glob): Globulins are the other group of protein that make up Total Protein. Some globulins (like albumin) also act as transport proteins, while others function as antibodies. Rare immunodeficiency disorders in puppies can cause low globulins. High globulins are more common as caused by chronic inflammation (chronic antigenic stimulation) and certain cancers (such as multiple myeloma and B cell lymphoma/leukemia). (If your vet is overly concerned at your pet’s elevated globulins, he or she may send-off a specialized serum protein electrophoresis test.)
- ALT: ALT, AST, ALP, and GGT are liver enzymes that become elevated primarily due to liver-related disease. Liver failure, as defined by the loss of the majority of functional hepatic cells, may result in normal to decreased liver enzyme values. Alanine amino transferase (ALT) may rise not only due to a plethora of liver diseases but also secondary to anemia (due to lack of oxygen transport to the liver secondary to an inadequate supply of red blood cells), seizures, diabetes mellitus, hyperthyroidism, certain infectious diseases (such as Leptospirosis and feline infectious peritonitis, or FIP), drug toxicity (such as phenobarbital, oral diazepam or Valium® use in cats, carprofen or Rimadyl® use in dogs), and xylitol toxicity.
- AST: Aspartate amino transferase will increase with the same mechanisms causing an elevation in ALT. Additionally, AST may also become increased with muscle injury and red blood cell destruction (hemolysis).
- ALP: Alkaline phosphatase (often referred to as Alk Phos) may be normally elevated in young, growing animals as well as certain dog breeds (such as Siberian huskies and Scottish terriers). Pathological (or abnormal) causes of high Alk Phos include cholestasis (a block of normal bile flow secondary to disease of the liver, gall bladder, and pancreas as well as diabetes mellitus, Cushing’s disease, and hyperthyroidism). Other triggers of high Alk Phos are certain medication use (phenobarbital, steroid use in dogs), bone disease, and various cancers (including canine mammary gland adenocarcinoma, a.k.a. “breast cancer”).
- GGT: Gamma glutamyl transferase will increase secondary to the same methods that cause high ALP.
- Total bilirubin (Bili): Bilirubin is a waste product created when old and dying red blood cells are eliminated from the body to make room for new, fresh red cells. Bilirubin is processed by the liver to be packaged into a form that can be transported through the bile duct to go to the intestines into feces and a small amount through the bloodstream to the kidneys into urine to then be eliminated out of the body. (Cool fact: bilirubin is responsible for poop’s brown color and pee’s yellow hue!) Causes of high bilirubin in the bloodstream (or hyperbilirubinemia) include red blood cell destruction (hemolysis), liver disease, or bile duct obstruction. Cats that have been fasted may also have elevated bilirubin on bloodwork. Direct bilirubin and indirect bilirubin are more specific means of measuring bilirubin levels and its actions in the bloodstream.
- Sodium (Na): Major electrolytes of the body include sodium (Na+), potassium (K+), chloride (Cl-), and bicarbonate (HCO3-). Sodium is important in maintaining appropriate fluid volume in the bloodstream and plasma osmolality (“blood saltiness” for lack of a better term) as well as aiding cellular electrical activity. If sodium is too out of whack, it can affect blood flow and brain function, potentially being deadly. High sodium levels can be caused by dehydration, fever, hyperventilation (such as excessive panting), central or nephrogenic diabetes insipidus, severe diarrhea, and excess salt toxicity. Causes of low sodium include loss from the body (via the kidneys, GI tract, or large skin wounds), rupture of the urinary bladder, or excess water-retentive states (such as congestive heart failure or liver failure). Sodium level is often analyzed along with a patient’s potassium level. For instance, a low sodium concentration with a very high potassium concentration (where the sodium to potassium ratio is less than 27:1) is suggestive of Addison’s disease (hypoadrenocorticism).
- Potassium (K): Like the other major electrolytes, potassium functions to conduct electricity throughout the body, primarily in the activity of muscles, including the heart muscle. Therefore, even slight potassium disturbances can cause severe side effects. Low potassium can result in severe weakness and muscle fatigue and can be caused by decreased dietary intake, acid-base disturbances (metabolic alkalosis), diabetic ketoacidosis (a potentially life-threatening state of diabetes mellitus), and increased loss from the body (via the kidneys or GI tract due to vomiting or diarrhea). An elevated potassium level is even more worrisome as deadly heart arrhythmias (abnormal heartbeats) and cardiac arrest can occur. High potassium concentrations can be caused by acid-base imbalances (metabolic acidosis), tissue death, failure of elimination via the urinary tract (due to urinary bladder rupture or obstruction of the urethra), or Addison’s disease. Occasionally, potassium may be elevated in a healthy patient, such as certain dog breeds (Akitas, Shiba Inus), or in patients with a high platelet count (platelets can release potassium inside blood test tubes).
- Chloride (Cl): Chloride is sodium’s lover. Wherever sodium goes, chloride tends to follow. If sodium and chloride are high, it’s usually due to water loss caused by fever, hyperventilation, diabetes insipidus, renal loss, or GI loss due to diarrhea. Low sodium and chloride can be caused by bodily loss (from the kidneys, GI tract, or skin wounds) or water retention. (Occasionally, a high triglyceride level can also cause chloride to appear low on the blood machine reading.) However, sometimes sodium and chloride have a lover’s quarrel and temporarily part ways. Certain GI diseases can cause chloride to be lower than sodium on the reference range: vomiting, gastric dilatation-volvulus (GDV) in dogs, and ileus (in which the intestines have decreased motility). Rarely, chloride can be high with a normal sodium due to certain kidney or GI disorders, although these situations are less common.
- TCO2: TCO2 stands for Total Carbon Dioxide and actually assesses bicarbonate (HCO3-), a major electrolyte. Bicarb helps maintain the body’s pH (balancing acids and bases in the body). High bicarb levels (a.k.a. high TCO2) is known as metabolic alkalosis (when there are more bases than acids in the body) and occurs when hydrogen atoms are lost from the GI tract or kidneys or in consequence to low potassium levels. A low bicarb level (and low TCO2) is called metabolic acidosis (when acids outnumber bases in the body) and can occur secondary to excessive hydrogen ion formation (due to build-up of products called ketones, lactic acid, or uremic acids, as well as from ethylene glycol/antifreeze toxicity) or due to decreased hydrogen ion excretion from the body (due to kidney failure, urethral blockage, urinary bladder rupture, or Addison’s disease). Low TCO2 can also occur with excessive loss of bicarbonate from the body due to severe vomiting or diarrhea.
- Anion Gap: Anion Gap is calculated from values of the body’s major electrolyte levels. A high anion gap means that the body is more acidic than it should be (a.k.a. metabolic acidosis), while a low anion gap can be secondary to low albumin or high calcium or magnesium.
- Triglyceride (Trig): Triglycerides are a storage form of fat typically found in fatty tissue (adipose). However, it may be elevated in the bloodstream following a meal (this is why it’s important for your pet to be fasted prior to bloodwork) or due to diabetes mellitus, Cushing’s disease, pancreatitis, hypothyroidism, and kidney disorders termed protein-losing nephropathies.
- Cholesterol (Chol): Cholesterol is another type of fat that makes steroid hormones and is also a component of cell membranes. It may be elevated, in addition to the above causes of high triglycerides, due to certain liver or gallbladder diseases (cholestasis, hepatic lipidosis in cats), or due to idiopathic hyperlipidemia of miniature schnauzers. Because cholesterol is made by the liver, it may be decreased secondarily to liver dysfunction (due to liver failure or portosystemic shunt); it may furthermore be low due to various GI disorders known as protein-losing enteropathies.
- Amylase (Amy): Amylase is a digestive enzyme to break down carbohydrates. It is produced by the pancreas, small intestine, and liver. Thus, it may be increased due to diseases of any of the aforementioned organs. Amylase is excreted from the body by the kidneys, so it will also be elevated due to kidney dysfunction and dehydration. Low amylase is not significant.
- Lipase (Lip): Lipase is a fat-processing digestive enzyme produced by the pancreas and stomach. Like amylase, lipase will also be elevated in pancreatic and GI diseases as well as liver and kidney diseases. Additionally, it may be high in patients receiving steroid therapy or those with Cushing’s disease.
Depending on your pet’s suspected or confirmed illness, your vet may order specialized blood tests to aid in his or her diagnosis. Such tests include but are not limited to infectious disease titers, thyroid hormone analysis (T4, fT4, T3, TSH), specialized liver tests (blood ammonia), Cushing’s or Addison’s disease tests (such as basal cortisol level, ACTH stimulation test, HDDS or LDDS tests, dexamethasone suppression test), insulin : glucose ratio, pancreas-assessment tests (PLI, TLI, cobalamin, folate), creatinine kinase, ionized calcium, PTH or PTHrP, SDMA for renal assessment, serum protein electrophoresis, tests to assess blood clotting (PT, PTT, ACT, TT, FDPs, D-dimers), and blood gas measurements.
Sheeeeeew!!! I know that was a lot to go over, and your brain may be swimming with “content overload,” but I promise you’ll thank me the next time your darling Mr. Fluffernutter or Miss CatNip-2-Chainz requires bloodwork. So don’t panic! Ask you vet plenty of questions and refer back to this article in the future when you need to better understand your pet’s blood results. Knowledge really is power! Now get on with your bad self, you smarty pants! 😉
Still curious about deciphering your pet’s lab results? Check out our tutorial on how to interpret your pet’s urinalysis.
Disclaimer: This information is for your basic understanding only. A holistic interpretation of your pet’s bloodwork is best left for your veterinarian’s expertise to decide the overall health of your pet and to initiate any treatments deemed necessary in the face of illness. Additionally, certain disease processes or machine errors may slightly alter how the following measurements are to be interpreted. Remember, like yourself, your dog or kitty is a complex organism with innumerable chemical reactions occurring across multiple organ systems, so no single lab test is going to answer all questions; it’s only a piece to the puzzle that is your pet.
– Maranda Elswick, DVM