Lipid Panel with Reflex to Direct LDL

Catalog information reviewed: August 24, 2026 by the Sunridge Medical clinical team.

What this laboratory test evaluates

Details

Lipid Panel with Reflex to Direct LDL
The Lipid Panel with Reflex to Direct LDL panel includes evaluation of total cholesterol, HDL-cholesterol, triglyceride (TG), LDL-cholesterol (calculated), cholesterol/HDL ratio (calculated), and non-HDL cholesterol; direct LDL-C measurement will be performed at additional cost if the TG level is >400 mg/dL. This panel is useful in the detection, classification, and monitoring of hyperlipidemia, especially those expected to have highly elevated TG levels.

LDL-C is widely accepted as a key factor for assessing the risk of coronary artery disease (CAD) [1]. The American Heart Association recommends lipid testing for adults over the age of 20 every 4 to 6 years [2]. Direct LDL-C measurement is more accurate than calculated LDL-C for patients with TG levels >400 mg/dL, and patients with hyperlipoproteinemia type III (dysbetalipoproteinemia). Thus, as indicated above, this panel is especially useful for individuals likely to have highly elevated TG and provides a basis for more realistic assessment of CAD risk in this group. It may also help track treatment progress by allowing healthcare practitioners to evaluate overall lipid levels, as well as direct LDL-C [3].

In addition to genetic causes that lead to highly elevated TG levels, certain medical conditions can also increase TG, including diabetes, thyroid disease, liver and kidney diseases, and obesity [4].

Calculated LDL values have a variance of 11% to 26%, whereas direct LDL-C values have a variance of less than 4% [5].

In rare cases, gammopathy, especially monoclonal IgM (Waldenstrom’s macroglobulinemia), may cause unreliable results.

References
1. Grundy SM, et al. Circulation. 2019;139:e1082-e1143.
2. Stone NJ, et al. Circulation. 2014;129 (suppl 2):S1-S45.
3. Armbruster DA, Lambert PA. Lab Med. 1996;9:613-617.
4. NHLBI. High blood triglycerides.
https://www.nhlbi.nih.gov/health-topics/high-blood-triglycerides.
5. Schectman G, et al. Clin Chem. 1994;39:1495-1503.

What type of sample is required for this test?2 mL serum

Test ResourcesFor more information, please consult your healthcare provider.

Additional test information

The Lipid Panel with Reflex to Direct LDL panel includes evaluation of total cholesterol, HDL-cholesterol, triglyceride (TG), LDL-cholesterol (calculated), cholesterol/HDL ratio (calculated), and non-HDL cholesterol; direct LDL-C measurement will be performed at additional cost if the TG level is >400 mg/dL. This panel is useful in the detection, classification, and monitoring of hyperlipidemia, especially those expected to have highly elevated TG levels.

Collection and processing

• Sample type: Serum
• Fasting: No
• Estimated laboratory processing: Results should be available in 2 – 5 business days after the sample is collected

How Sunridge uses laboratory information

Sunridge considers the medical question, symptoms, history, medications, prior results, and whether the finding could change care before recommending testing. A laboratory result is not interpreted in isolation and does not establish a diagnosis by itself.

Before requesting this test

Availability, collection requirements, eligibility, and processing estimates can change. Sunridge reviews each request and, when appropriate, creates the order through Fullscript. Follow the current instructions supplied with the approved order.