Cardio Risk app incorrectly calculates LDL

[jmandel]

The app is estimating Total Cholesterol - HDL. this is an overestimate of LDLs, since it doesn't take triglycerides into account. Should either:

1. Look for an actual LDL lab result
2. Look for a triglyceride reading and estimate LDL = Total Cholesterol - HDL - Triglycerides / 5

[p2]

The commonly used Friedewald formula for LDL is:

LDL = Total Cholesterol - VLDL - HDL

Edit: Too fast with submitting. VLDL can be calculated from Triglycerides (if they are below 4 mmol/L / 350 mg/dL):

VLDL = Trig / 2.2 [mmol/L]
VLDL = Trig / 5 [mg/dL or g/L]

Edit 2: Now I see that that's what you're using, I was used to the 2.2. :D
Nevermind.

[jmandel]

No, being explicit about units is important! The current app is also fragile in that regard...

I just did a quick 'spike' to explore porting the app to HL7's FHIR, and had to add units conversion in the process:
code: https://github.com/chb/fhir_cardiac_risk/blob/gh-pages/load_data.js
demo: http://chb.github.com/fhir_cardiac_risk?personId=1