3 Step ABG Interpretation
Mike’s Marching Band Suit Method
How to Solve ABG Questions in 3 Steps
Step 1 - pH
pH is primary, look here first
pH below 7.35 = Acidosis
pH
Primary
pH over 7.45 = Base (Alkalosis)
pH
PaCO₂
HCO₃
Step 2 - Match pH with partner
Example:
Let’s say pH is under 7.35, PaCO2 is
over 45 & HCO3 is normal 2 acids match:
pH & CO2 = Respiratory Acidosis
!
pH
!
!
(look at the organ icon to help you)
B
7.35
7.45
B
A
35
45
A
B
22
26
A
B
7.35
7.45
A
B
PaCO₂
Acidosis
A
35
A
HCO₃
45
B
Normal
22
26
Step 3 - Compensated or Uncompensated
Fully Compensated
MEMORY TRICK
Compensation means finding common
ground to make the pH within normal range.
pH
Uncompensated = pH is OUTSIDE normal range
The “broken home”. The body is NOT TRYING to
help balance the pH.
It’s like having a lazy partner in a relationship!
Step 3 - Compensated or Uncompensated
Partially compensated = pH is OUTSIDE normal range,
but the body is trying!
It is like couples counseling, sure the pH is NOT normal,
but at least the lungs & kidneys are TRYING to work things
out.
B
7.43
7.45
A
35
45
B
A
HCO₃
Step 3 - Compensated or Uncompensated
Normal
B
PaCO₂
Fully Compensated = pH is within normal range
The lungs & kidneys are doing their part to
balance the body
A
7.35
22
26
Uncompensated
Memory Trick
UNcompensated is very
UNfriendly
pH
A
B
7.35
7.45
A
B
PaCO₂
35
HCO₃
45
A
Normal
B
22
25
26
Partially compensated
pH
PaCO₂
HCO₃
A
B
7.35
7.45
A
B
35
45
A
22
26
A
B
42