What does it measure?
AIP is the base-10 logarithm of triglycerides divided by HDL cholesterol, with both first expressed in mmol/L. The original work studied how it related to lipoprotein particle size and cholesterol handling. It is derived from a lipid panel, not a direct scan of artery plaque. [1]
Before reading the calculation
- Inputs
- Triglycerides and HDL cholesterol, both converted to mmol/L.
- Calculation
- AIP = log10(triglycerides ÷ HDL). This logarithmic index is different from the plain TG/HDL ratio.
What can the result mean?
A higher AIP generally corresponds to a pattern of higher triglycerides relative to HDL. It has been associated with cardiometabolic risk in research, but it does not diagnose blocked arteries or establish a treatment plan. A low result cannot cancel other risks such as high LDL or smoking. [1]
Triglycerides and HDL cholesterol, both converted to mmol/L.
- Calculation
- AIP = log10(triglycerides ÷ HDL). This logarithmic index is different from the plain TG/HDL ratio.
When is it useful, and how is it read?
AIP summarizes a lipid pattern studied in relation to lipoprotein characteristics. It does not count particles or replace a cardiovascular risk assessment. Look at the original triglycerides, HDL, and established cholesterol measures before attaching meaning to the index. [1]
What can affect it?
The molar units are essential: entering raw mg/dL values gives a different, incorrect AIP. Meals, illness, and medicines can change the lipid inputs. Proposed categories differ across studies, and a universal target for individual preventive care has not been established. [1]
A negative number is mathematically possible
AIP uses the base-10 logarithm of TG divided by HDL in molar units. When that ratio is below one, its logarithm is negative. A negative AIP is therefore not automatically a calculation error or a guarantee of protection. [1]
Questions you might have
Can I enter mg/dL values directly?
No. The published calculation uses molar concentrations. Convert both inputs correctly before taking the ratio and its logarithm. [2]
Does AIP show how much plaque is in my arteries?
No. It summarizes a lipid pattern studied against lipoprotein characteristics; it does not image or measure artery plaque. [2]
What comes next?
Before focusing on this index, review the actual triglycerides, LDL, non-HDL, and overall cardiovascular risk. Ask whether AIP would change a decision. If it does not, your effort is better directed toward the specific risks and actions already supported by clinical evidence.
Would this index change my care, or are the original lipid results enough to guide us?
The reference interval and units on your report are part of understanding your result. Understand units, reference intervals, and treatment targets.
Sources & references
Medical references & original research
- Dobiášová and Frohlich — Original AIP study (PubMed, 2001)
- Dobiášová and Frohlich — The plasma parameter log(TG/HDL-C) (2001)
Books we consulted
References that informed our explanations of the test and its context.
- Pagana KD, Pagana TJ, Pagana TN. Mosby’s Diagnostic and Laboratory Test Reference. 14th ed. Elsevier; 2019.
Practical-section sources accessed: .
For general health education. Interpreting your result and deciding on tests or treatment requires your health context and a qualified clinician.
