# Formulas for step 1

#### starry sky

##### Junior Member
10+ Year Member
So, I was wondering if any of you encountered questions that required you to use respiratory formulas (e.g. alveolar-arterial O2 difference, physiologic dead space) or renal formulas (acid-base compensation, renal clearance, etc.) on step 1. I have less than a week until my exam and I don't want to waste my "brain space" on memorizing formulas I don't need to know. I realize everyone's test is different, but any input would be appreciated

#### OSUdoc08

##### Membership Revoked
Removed
15+ Year Member
starry sky said:
So, I was wondering if any of you encountered questions that required you to use respiratory formulas (e.g. alveolar-arterial O2 difference, physiologic dead space) or renal formulas (acid-base compensation, renal clearance, etc.) on step 1. I have less than a week until my exam and I don't want to waste my "brain space" on memorizing formulas I don't need to know. I realize everyone's test is different, but any input would be appreciated
The majority of formulas on mine were biostats.

#### SaltySqueegee

##### El Rey de Salsa
10+ Year Member
15+ Year Member
Biostats was the majority for mine as well.

However, it is important to know...

...how to estimate GFR from inulin and creatinine clearance.
...the equation for cardiac output and its variants, and how it can relate to oxygen usage. Ficks approx. method showed up on my test.

#### lord_jeebus

##### 和魂洋才
Moderator
15+ Year Member
I had to calculate alveolar-arterial O2 difference.

#### scottj00

##### Junior Member
7+ Year Member
15+ Year Member
1. calculate resistance/flow across resistors in series/parallel
2. calculate positive/neg predictive values
3. what is significance of p value
5. What factors influence the power of a research study

C

#### CaptainZero

1) C.O. when given arterial/venous O2 values
2) Resistances in parallel
3) Postive Predictive Value
4) MAP
5) Infusion rate of drug needed to reach a given steady state concentration given some pharmacokinetic properties of the drug.
6) I had a population genetics question...which I skipped. (The time it takes me to work through those questions makes them not worth doing on a timed test)
7) clearance of a substance

#### dmitrinyr

##### Senior Member
10+ Year Member
15+ Year Member
I just took the test yesterday.

There were only about 5-7 questions for which you needed to know a formula and 4-5 of those were biostat/epi questions that were extremely simple if you just knew the formulas (the questions literally asked: what is the sensitivity of this research?). As far as non-biostat questions, i had one question asking me to calculate SV when they gave me HR and A-V O2 content difference and the other part of the formula for CO (it just slipped my mind as i'm writing this post). Frankly, I think the only formulas you should try to know are cardio physio formulas and biostat/epi formulas.

OP

#### starry sky

##### Junior Member
10+ Year Member
I guess I can answer my own question now since I took my test a few days ago. I didn't have many questions at all requiring formulas. A few simple biostats and genetics/probability questions. Hope that helps someone out there.

#### PlasticC

Does anyone else remember formulas they ended up using on step 1?