CBC

What is in a CBC?

WBC, hemoglobin, hematocrit, platelets

 

What are normal lab values for CBC?

• Note: normal values vary between labs
• WBC              4.8-10.8 k/μL
• Hemoglobin   ♂ 14.0-18.0 g/dL, ♀ 12-16 g/dL
• Hematocrit    ♂ 42-52%, ♀ 37-47%
• Platelets        145-400 k/μL

 

With an infection, what is expected to happen to the WBC count after surgery?

Eventually it should go down, but in post-op days 1-2, the WBC may actually increase a bit.

This is may occur because surgery activates the body's reaction to the infection.

 

What should be done if the patient’s WBC is over 10?

First, decide if the patient has an infection

• If there is an infection, then antibiotics and possible incision and drainage (I&D) should decrease the WBC count
• If there is not an infection, then the cause must be determined. Is the increase acute or chronic? Is there another source of infection (other than the foot)? Is the patient on corticosteroids? Is there a combination of medical conditions causing this?

 

What to do if platelets are low (under 150-350 k/mL)?

Can transfuse platelets, but this is not commonly done

 

What are the minimum levels for hemoglobin and hematocrit for elective surgery?

Hemoglobin 10 gm/dL and Hct 30%

 

What should be done if the Hemoglobin/Hematocrit (H/H) is below 10/30?

If necessary, transfuse 1-2 units of packed red blood cells (PRBC)

• Called Anemia

 

What are causes of microcytic, hypochromic anemia?

Iron deficiency, thalassemias, lead poisoning

 

What are causes of macrocytic, megaloblastic anemia?

Vitamin B12/folate deficiency

 

Following a transfusion of PRBC, when will changes in the H/H be seen?

Approximately 3 hours. Therefore, order new labs to be drawn 4 hours after last unit given.

 

BMP

What is in a BMP?

Sodium, potassium, chloride, carbon dioxide, BUN, creatinine, glucose

 

What is in a CMP?

BMP with ALP (alkaline phosphatase), ALT (alanine amino transferase, also called SGPT),

AST (aspartate amino transferase, also called SGOT), bilirubin, albumin, total protein, calcium

 

What are normal values for BMP?

• Note: normal values vary between labs
• Sodium         135-146 mmol/L
• Potassium     3.5-5.1 mmol/L
• Chloride        96-106 mmol/L
• CO2              24-32 mmol/L
• BUN              10-20 mg/dL
• Creatinine     0.7-1.3 mg/dL
• Glucose        70-110 mg/dL

 

What do Na+, K+, Cl and CO2 tell you?

These electrolytes indicate nutritional status

 

What should be done if Na+ is low?

Give NSS or regular salt

 

What should be done if K+ is too low?

Hypokalemia may cause cardiac arrhythmias, muscle weakness, paresthesias, cramps

Manage hypokalemia

 Give K-Dur (potassium chloride supplement)

 Give potassium-rich foods (i.e. banana)

 

What should be done if the K+ is too high?

Hyperkalemia may cause cardiac arrhythmias, lethargy, respiratory depression, coma

Order EKG

Manage hyperkalemia

• Calcium gluconate
• Sodium bicarbonate
• Dextrose with insulin
• Kayexalate

 

What do BUN and creatinine indicate?

Renal function

 

What should be done if the creatinine is too high?

Consult renal if creat is over 1.5 for a couple of results

Note: creat may be increased after muscle breakdown or loss

 

Which is a more important indicator – BUN or creatinine?

Creat is more important, because BUN is influenced by hydration state. If the BUN is high but

creat is normal, then the patient is most likely dehydrated and rehydration should correct the

BUN. However, if both BUN and creat are high, then the patient most likely has renal damage.

 

PT/PTT/INR

What do PT/PTT/INR tell you?

The coagulable state of the patient. If the levels are high, it will take longer for the patient to

develop a clot and stop bleeding. It requires blockage of only one pathway to anticoagulate the

patient.

 

What are normal values for PT/PTT/INR?

• Note: normal values vary between labs
• PT       11.7-14.5 sec
• INR      0.9-1.1
• PTT      23-36 sec

 

What can cause an elevated PT/INR?

Coumadin

Malnutrition

Alcoholism

Antibiotics

Vitamin K disorders

 

What does INR stand for? Why was it developed?

International Normalized Ratio

There are different methods to determine PT, and thus each lab has a different normal value for

PT. INR was devised to standardize all the results.

 

If the patient is on Coumadin for anticoagulation, what should the INR be?

Intense anticoagulation 2-3

 

What causes the PTT to be high?

Heparin

 

Which pathway does PTT check?

Intrinsic ("PITT")

 

Which pathway does PT check?

Extrinsic ("PET")