1. Practical Clinical Pathology The Serum Profile
Wendy Blount, DVM

2. Emergency Quick Assessment
Immediate: PCV/TP, glucose, BUN
Get samples to run later
Blood (8-10cc)
EDTA tube (2-3cc)
Lithium heparin tube (2-3cc)
Potassium citrate tube (2-3cc)
Red top clot tube (2-3cc)
urine

3. Emergency Quick Assessment
Urinalysis
If you need a urinalysis later, you need a sample prior to fluid therapy, before specific gravity is diluted
If fever, you may want urine for possible culture prior to antibiotic therapy
Use a 5-8Fr x 36” infant feeding tube to catheterize male dog > 75 pounds
Use US guidance if needed for cystocentesis of small bladder

4. Emergency Quick Assessment
Indications for Diagnostic Abdominocentesis
Palpable fluid wave
Owner reports abdominal bloating
Suspect abdominal hemorrhage
Acute collapse, pale mucous membranes, weak pulses, low blood pressure, + anemia
Suspect peritonitis – shock and abdominal pain
Fluid seen on AFAST® ultrasound

5. Emergency Quick Assessment
Diagnostic abdominal tap technique
4 quadrants - R cranial, L cranial, R caudal, L caudal
Diagnostic Peritoneal Lavage

6. Emergency Quick Assessment
AFAST® Technique
HR site – half way between umbilicus and table (R lateral)
20-22g 1-1/2 needle or butterfly
no syringe – gravity drip into tubes
Put fluid in EDTA and red top tubes for analysis
EDTA - Spin down & direct for cytology
red top tube for culture if needed (closed - syringe)
Run EDTA through CBC machine for cell counts
Fluid Analysis Handout

7. Ascites Transudate or Modified Transudate
Remove enough fluid to alleviate dyspnea, and allow comfortable chest x-rays & abdominal ultrasound
Bloodwork and abdominal ultrasound to determine the cause, and treat accordingly
If cause is congestive heart failure, remove all fluid
Hemorrhage - usually a surgical problem, unless
Coagulopathy or anaphylaxis is identified and treated
Traumatic hemorrhage resolves spontaneously (serial AFAST®), + auto-transfusion
Non-septic exudate, chyle – tap if dyspneic
Rarely surgical

8. Ascites
Septic exudate, uroabdomen, bile peritonitis – usually surgical
Multiple species of bacteria suggest GI perforation
Plant material is very strong evidence
If no bacteria are seen, look for phagocytosed bacteria in WBC, and for toxic changes in the neutrophils
Feline Infectious Peritonitis (FIP) fluid
High protein – mucoid strings (TP > 5-10 g/dl)
Cell count usually <5,000/ul & almost always <10,000/ul
Mononuclear cells usually > segs
Albumin:glob usually <0.8: <0.45 is strong evidence

9. Ascites Compare abdominal fluid to plasma/serum
Abdominal amylase and lipase > plasma/serum
Pancreatitis
Abdominal fluid glucose <50 mg/dl and <plasma/serum
often indicative of bacterial peritonitis
Abdominal bilirubin > plasma/serum
Gallbladder/biliary tract rupture
Abdominal creat > plasma/serum (BUN the same)
Ruptured urinary tract
Abd. triglycerides > serum; Abd. Cholesterol < serum
chyle
Abdominal coronavirus PCR or AB titer >> serum
FIP

10. The Great Pretender Hypoglycemia and Addison’s
Glucocorticoids increase gluconeogenesis while decreasing glucose use in tissues via increase insulin receptor sensitivity
May be more common in toy breeds where there are other predispositions to hypoglycemia
Can be severe enough to cause seizures
20-25% of Addisonians are hypoglycemic
Responds the therapy in hours

11. The Great Pretender Hypoalbuminemia and Addison’s
Albumin may have been contributed to also by lung infection in this case
Hypoalbuminemia can be the primary presenting symptom of Addison’s

12. The Great Pretender Azotemia and Addison’s
Hypovolemia causing decreased renal perfusion and prerenal azotemia
Can result in renal injury and renal azotemia if severe, prolonged and untreated
Hemorrhage in the GI tract can result in increased BUN
GI bleeding leads to more ammonia in the colon
Ammonia converted to urea in the liver

13. The Great Pretender Azotemia and Addison’s
Increased BUN, creat and/or phos
If no renal injury, azotemia responds quickly to fluid therapy – but relapses
Responds even better if DexSP given for shock
Urine specific gravity
Often mildly concentrated urine
Can also be isosthenuric or hyposthenuric due to medullary washout

14. The Great Pretender Hypercalcemia and Addison’s
More likely in Addisonians with more severe disease and hyperkalemia
29% of primary Addisonians are hypercalcemic
Mechanism – unsure
Possible hemoconcentrations of calcium binding serum proteins
Decreased renal clearance of calcium
Cortisol antagonizes vitamin D
Responds rapidly to glucocorticoid therapy

15. Na:K Ratio Thumb Rules Adrenal (primary) Addison’s
86% have hyponatremia (<142 mEq/L)
95% have hyperkalemia (>5.5 mEq/L)
4% have normal K, Na and Cl
ACTH deficiency (secondary HypoAC)
35% have hyponatremia
Unlikely to cause hyperkalemia
Clinical glucocorticoid deficiency
Addisonians almost never have low potassium or high sodium
Decreased Na:K is highly specific but not sensitive at all for Addison’s disease

16. Na:K Ratio
However….
Dehydration can mask hyponatremia and hypochloremia
Adrenal Addison's disease can be purely glucocorticoid deficiency which has a less marked effect on electrolytes
Abnormalities can be subtle

17. Na:K Ratio
Mike Willard was amongst the earliest veterinary authors to embrace Na:K <27-28 as a diagnostic method for Addison's
Mike Willard, 2005 – personal conversation
“I wish I had never written that paper”

18. Na:K Ratio Conclusions There are many causes of Na:K < 27-28
Only 15-17% of these are Addisonian
Other causes include:
Abdominal or thoracic effusion
Cardiorespiratory disease
Acidosis
Trauma or reperfusion injury
Sepsis
Diabetic Ketoacidosis
Uremia (oliguric renal failure, obstruction/rupture)

19. Na:K Ratio Conclusions Other causes include: Liver failure Toxicity
Mushrooms, IV fluid therapy or TPN, K sparing diuretics (spironolactone), ACE inhibitors, NSAIDs
Artifacts
Extreme leukocytosis
Hemolysis in Akitas and Shiba inus
Running serology on EDTA plasma

20. Na:K Ratio Conclusions Other causes include: GI disease
Whipworms, hookworms
Pancreatitis
GDV
ulcers, especially if perforation
Canine parvovirus
Canine distemper virus
severe malabsorption**
Severe deep pyoderma

21. Na:K Ratio Conclusions – The Bottom Line
Most Addisonians that lack both gluco- and mineralocorticoid deficiencies have Na:K <27
Na:K <24 is a stronger indicator of hypoAC
Na:K <15 is even stronger for Addisons
Na:K >28 makes Addison's unlikely

22. Diabetes Mellitus Hyperglycemia (of course) Indications of DKA
Low HCO3, low TCO2, low pH, high anion gap, ketonuria
Indicates: ICU care, higher level of IV potassium supplementation, more phosphates
Insulin carries K+ & Phos into the cell
Correcting acidosis makes low serum K+ worse
Phos <1.5 can cause severe hemolysis
Low K+ can cause weakness and paralysis
Pancreatitis pattern – need fluid support
Fatty liver pattern – feed cats

23. K+ & Phos in DKA Patient
Monitor PCV, K+ and Phos at least daily until stable, in DKA patients
More often if very low or unstable
Can use 0.5cc lithium heparin tubes to prevent exsanguination
Place jugular catheter for patient comfort
Draw blood without venipuncture
Replace K+ according to sliding scale
More K+ supplemented when acidotic
The lower Phos, the more KPhos:KCl you use
Don’t exceed 0.5 mEq/kg/hr potassium

24. K+ & Phos in DKA Patient Eating is important to maintaining K+/Phos
usually stabilize when the cat begins to eat
REMEMBER
KCl contains 2 mEq/ml potassium
KPhosphates contain 4 mEq/ml potassium
Use half the volume of KCl as KPhos for the same amount of potassium added to fluids
Be VERY CAREFUL of bicarbonate therapy
I almost never give bicarb to DKA patients
Bicarbonate can exacerbate low Phos and K
Regular insulin given PRN to keep glucose , checking glucose q2-4 hrs

25. Insulinoma CBC and UA normal Serum panel
Hypoglycemia - mean mg/dl
Usually below 60
Can be as low as 15
The rest often normal
May assume serum sat on the cells
Early on, hour fast may be required to detect hypoglycemia

26. Hypoglycemia Hypoglycemia in a puppy or kitten Juvenile hypoglycemia
starvation
Portasystemic shunt
Sepsis
Young adult dogs or cats
PSS or other hepatobiliary disease
Hypoadrenocorticism (dog >> cat)

27. Hypoglycemia Geriatric dogs or cats hepatobiliary disease
Beta cell neoplasia (insulinoma)
Extrapancreatic neoplasia
Hypoadrenocorticism
Sepsis
Moderate hypoglycemia (45-60 mg/dl)
Hepatobiliary disease

28. Hypoglycemia Severe Hypoglycemia (<40 mg/dl)
Toy breed, juvenile hypoglycemia
Beta cell neoplasia (insulinoma)
Extrapancreatic neoplasia
Especially liver and smooth muscle tumors
Sepsis, Seizures

29. Liver Disease High liver enzymes Low albumin
ALT – hepatocellular disease
SAP, GGT – more sensitive indicator of
cholestasis than bilirubin (from biliary epithelium)
Low albumin
other proteins low first (low alb indicates severe disease)
Beware human labs (falsely low values)
Low fasting glucose (70% loss of hepatic mass)
High prost-prandial glucose
Low BUN
Abnormal cholesterol, triglycerides

30. Liver Disease Weight loss, anorexia common
Prolonged recovery from anesthesia
Ascites – transudate or modified transudate
Increased sodium retention, portal hypertension, hypoalbuminemia
PU-PD
Acholic feces
Dark urine (orange) precedes icterus
Ammonium biurate crystalluria or stones
think PSS (33-50% sensitive)
Icterus
Seen best on sclerae, penile mucosa, soft palate, under the tongue

31. Liver Disease Tendency to sepsis GI hemorrhage death spiral
Hepatic RE system detoxifies blood from the gut (portal circulation)
GI hemorrhage death spiral
Decreased hepatic clearance of gastrin
Clotting factor’s, AT3 not produced adequately
Increased bile acids stimulated HCl secretion
DIC
Bleeding exacerbates hepatic encephalopathy
Large bleed can cause depletion coagulopathy
Hemorrhage elsewhere only when near death
Petechiae, bruising, bleeding into cavities

32. Liver Disease PSS in Cats most common clinical sign
salivation
Hepatic encephalopathy
Symptoms after a meal
Mutlifocal CNS disease
Vomiting and diarrhea

33. Pancreatitis CBC – nonspecific Thrombocytopenia
Neutrophilia with left shift
Anemia
Serology
Lipemia after a prolonged fast (TG, chol)
Can present for opaque eyes or anterior uveitis
Lipemia in the cat is rare, and should prompt ruling out pancreatitis
Hypocalcemia – why?
Calcium consumed by saponification of fat
Hypoalbuminemia – why?
Massive inflammation, vasculitis, + sepsis

34. Pancreatitis Serology – Dogs and Cats Nonspecific changes
Elevated liver enzymes
Elevated bilirubin
Azotemia
Hyperglycemia (cause or effect)
Hypoglycemia
Hypophosphatemia – why? acidosis
Hypochloridemia – why? vomiting
Amylase seldom helpful, lipase a weak indicator

35. Pancreatitis Serology – Dogs only Amylase Lipase Serology – Cats only
normal in 47%
Lipase
Normal in 61%
Serology – Cats only
Elevated cholesterol (less often than triglycerides)
Amylase and lipase not at all useful
Assays measuring lipase are enzymatic assays
Measure the amount of substrate the lipase consumes
Measure lipase activity, not quantity of lipase
Digestive lipases
intestinal lumen  intestinal epithelial cells
Intestinal acidic lipase
intestinal epithelial cells  vascular space
Lipoprotein lipase and hepatic lipase
vascular space  tissue cells
Hormone-sensitive lipase
adipocyte  vascular space
Lysosomal acidic lipase
tissue cells  vascular space

36. Pancreatitis GI Serology – Dogs and Cats B12 may be low – why?
Intrinsic factor from the pancreas is required for absorption (cats)
concurrent distal small intestinal disease (ileum)
Concurrent dysbiosis
Concurrent EPI
SUBNORMAL B12 NOT DUE TO DIETARY INSUFFICIENCY
But it can be corrected by giving B12 PO

37. Pancreatitis
GI Serology – Dogs and Cats -
SC once weekly for 6 weeks, then every 30 days, or as indicated by monitoring
<10 lbs – 250 mcg
10-20 lbs – 400 mcg
20-40 lbs – 600 mcg
60-80 lbs – 1000 mcg
lbs – 1200 mcg
>100 lbs – 1500 mcg
PO daily x 30d, then as indicated by monitoring DOGS
<20 lbs – 250 mcg, lbs – 500 mcg, >40 lbs – 1000 mcg
Cobalequin® - Nutramax Lab
ACVIM 2015

38. Pancreatitis GI Serology – Dogs and Cats
Folate may be high if dysbiosis
Folate may be low if proximal small intestinal disease
Not as often supplemented, but can be in severe chronic intestinal disease
indicator for further diagnostics

39. Pancreatitis GI Serology – Dogs and Cats
TLI (trypsin like immunoreactivity)
Low value is highly specific for EPI
Increased in SOME dogs and cats with pancreatitis
Increase is short lived – may begin to wane soon after acute onset

40. Pancreatitis GI Serology – Dogs and Cats
What is the BEST blood test to diagnose pancreatitis??
cPLI (canine Pancreatic Lipase Immunoreactivity)
97% sensitive for pancreatitis
82% specific for pancreatitis (18% false positives)
fPLI (feline Pancreatic Lipase Immunoreactivity)
Low confidence in this test amongst some feline specialists
100% sensitive for severe pancreatitis, 54% for mild
100% specific in healthy cats, 67% sensitive in sick cats
Much more sensitive and specific for pancreatitis
than any other blood test or imaging in dogs
Antech and IDEXX
TAMU GI Lab (TVMDL sends to TAMU)

41. Diagnostic tools: A comparison

42. SNAP cPL for Screening Dog w/ Vomiting, Anorexia, Abdominal pain CBC
Profile/lytes UA
SNAP cPL
SNAP Abnormal
SNAP Normal
>400
Treat for pancreatitis,
Baseline cPLI
Abdominal radiographs
Abdominal US
Baseline cPLI
Pancreatitis is unlikely – pursue other differential diagnoses
monitor w/ cPLI
IDEXX then encourages a Spec cPL test be run through our reference laboratories to baseline cPL concentrations and monitor response to treatment.
US/Rads confirm
pancreatitis
US/Rads equivocal
Treat, Monitor, Retest; Continue to rule out other differential diagnoses
Treat for pancreatitis,
Monitor with cPLI

43. Pancreatitis Urinalysis – nonspecific Ketones Transient proteinuria
think diabetic with ketoacidosis (if glucosuria)
Or prolonged fasting/starvation (if no glucosuria)
Transient proteinuria
Enzyme mediated glomerular damage

44. Pancreatitis Coagulation panel Thrombocytopenia DIC
Vasculitis (enzyme mediated), DIC
DIC
PT, PTT, ACT
Elevated
FDP, d-Dimers (Cornell Coag Lab)
(payment form, Guidelines, Shipping, Labels)
high

45. Pancreatitis Electrolyte panel/blood gases (venous is fine)
HCO3,TC02, pH, pC02
Low - Metabolic acidosis
What clue will your patient give you to check venous blood gases?
Panting
Potassium
Low – why?
H+ outside the cell exchanged for K+ inside the cell
K+ lost in the urine
Especially a problem with diabetics – why?
Insulin is required to get potassium into the cell where it is needed and stored

46. Pancreatitis Treatment: Dogs and Cats
Fluid therapy – why so crucial
Add glucose if hypoglycemic
Add bicarbonate if:
Acidosis is immediately life threatening
Acidosis will not be corrected by treating other problems
See handout
LRS won’t work if severe liver disease and needs alkalinizing – why??
Liver must transform lactate to bicarbonate

47. Pancreatitis Treatment: Dogs and Cats
“Flop”
Chief Complaint – Not doing well since treating abscess on a toe 1 week ago, vomiting blood
3 days ago regular vet did a UA and blood glucose
UA showed ketones++ and glucose +++, blood glucose 296
Has been treating with IV fluids since, getting worse
Did not start insulin because cat not eating
Exam - Dehydrated, lethargic, icteric, RR 56
vomited coffee grounds and collapsed on abdominal palpation, HR 65/bpm
Responded to atropine IV and fluid bolus

48. Pancreatitis Treatment: Dogs and Cats
“Flop” - diagnostics
CBC – granulocytes 16,000
Profile – glucose 200, BUN 41
TG 500, Chol 297
Bili 4.2, ALT 148, ALP normal
Ca 7.0, Phos 1.6
UA – SG 1.027, ketones ++, glucose +++, inactive sediment
Electrolytes – K+ <2.0, Na+ 133, iCa
pH 7.032, BE -24, HCO3 7, TCO2 8
pCO2 26.5,
No chest rads or abdominal US done
Urine culture pending

49. Pancreatitis Treatment: Dogs and Cats
“Flop” - treatment
IV fluids – of course – 45 ml/lb/day
Rehydrates and corrects acidosis – which fluids?
Buffered – LRS, Ringers, Normosol, Plasmalyte, etc.
Potassium chloride – no – need phosphorus
Potassium phosphates – 100 max safe rate
Insulin – wait 2 hours
Advantage – corrects ketoacidosis
Disadvantage – makes hypokalemia and hyposphatemia worse
Bicarbonate – no
Advantage – corrects acidosis
Disadvantage – will make hypokalemia worse
Cefazolin 100 mg IV TID, famotidine 5 mg IV BID
Cerenia®, Pain meds later with insulin

50. Pancreatitis Treatment: Dogs and Cats
“Flop” – reassess in 4 hours
Glucose - 99 (gave 1 unit NPH SC)
PCV – 23%
pH 7.228, HC03 10, TCO2 11
pC ,
iCa , Na+ 130, K+ 2.3
Phosphorus 0.7
Red tinged urine, serum icteric
Hydration normal, general condition slightly improved, no vomiting, not eating

51. Pancreatitis Treatment: Dogs and Cats
“Flop” – 2 days later
Glucose - 325
PCV – 20%
pH 7.403, HC , TCO2 20
pC02 30
iCa , Na+ 134, K+ 3.7
Phosphorus 3.4
Urine clear, serum slightly icteric
Hydration normal, general condition greatly improved, eating small amounts, no vomiting

52. Protein Losing Enteropathy
Panel more often normal with LI diarrhea , except Boxer Colitis
Low albumin - SI disease and Boxer Colitis
Low albumin and globulin, with anemia - GI bleeding
Especially if BUN increased and creat/phos normal