Lipid Panel with Reflex to Direct LDL

Test Code

CPT Codes

Cholesterol, Total
HDL Cholesterol
LDL-Cholesterol (calculated)
Cholesterol/HDL Ratio (calculated)
Non-HDL Cholesterol (calculated)

If Triglyceride result is >400 mg/dL, then Direct LDL will be performed at an additional charge (CPT code(s): 83721).

Preferred Specimen
2 mL serum

Patient Preparation
Fasting is not required prior to collection of a lipid panel.
The assay manufacturer Beckman Coulter advises: "N-Acetyl Cysteine (NAC), when administered in therapeutic concentrations (for the treatment of acetaminophen overdose), has been determined to interfere with assays for cholesterol, uric acid" where "NAC interference may lead to falsely low results." According to Beckman Coulter, the NAC interference should be insignificant by 12 hours after completion of the initial loading dose of an IV infusion treatment regimen consisting of an initial loading dose of 150 mg/kg administered over 1 hour, a second dose of 50 mg/kg administered over 4 hours and a third dose of 100 mg/kg administered over 16 hours.

Minimum Volume
1 mL

Other Acceptable Specimens
Plasma collected in: sodium heparin (green-top) tube, or lithium heparin (green-top) tube

Note: See individual tests for specific specimen requirements.
Centrifuge within 30-60 minutes following collection.

Transport Temperature
Refrigerated (cold packs)

Specimen Stability
Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 28 days

Room temperature: 48 hours
Refrigerated: 48 hours
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Moderate to gross icterus • Anticoagulants other than heparin

Spectrophotometry (SP)

Setup Schedule
Monday-Sunday Morning Report available: Next Day

Reference Range

Total Cholesterol
<20 Years <170 <170
≥20 Years <200 <200
HDL Cholesterol    
<20 Years >45 >45
≥20 Years ≥40 ≥50
≤9 Years <75 <75
10-19 Years <90 <90
≥20 Years <150 <150
LDL-Cholesterol (Calc)    
<20 Years <110 <110
≥20 Years <100 <100
Cholesterol/HDL Ratio (Calc) <5.0 <5.0
Non-HDL Cholesterol    
<20 Years <120 <120
≥20 Years <130 <130

Clinical Significance
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.

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.
5. Schectman G, et al. Clin Chem. 1994;39:1495-1503.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.