Neutrophil to Lymphocyte Ratio
(NLR)

Sample type:

• Lavender-top (EDTA) tube.

Uses:

• NLR (Neutrophil to Lymphocyte Ratio) is a biomarker that can be used as an indication of subclinical inflammation.

• NLR is a calculation based on the Absolute Neutrophil Count divided by the Absolute Lymphocyte Count determined by the peripheral blood CBC differential.

• This calculation, according to recent literature, is useful in assessing the likelihood of severe progression of disease in SARS-CoV-2 positive patients.

Precautions:

• Maintain specimen at room temperature.

• Avoid infecton of patient before taking the sample.

• Don’t take oral heparin before the test.

Interfering Factors:

• High NLR in patients with septic shock and bacteremia.

• High in cardio chock.

• High in massive pulmonary embolism.

Pre analytical errors:

1. Inappropriate specimen received.

2. Unlabeled specimen or name discrepancy between specimen and request label;

3. Specimen received after prolonged delay (usually more than 72 hours);

4. Specimen received in expired transport container.

Corrective action:

1. Appropriate specimen received.

2. Labeled specimen and no name discrepancy between specimen and request label.

3. Specimen received without delay.

4. Specimen received in valid transport container.

Post analytical errors:

1. Failure in reporting.

2. Erroneous validation of analytical data.

3. Improper data entry.

Corrective action:

1. Write correct report.

2. All analytical data should be valid.

3. Proper data entry.

Reference range:

• A normal NLR is roughly 1-3.

• An NLR of 6-9 suggests mild stress (e.g. a patient with uncomplicated appendicitis).

• Critically ill patients will often have an NLR of ~9 or higher (occasionally reaching values close to 100).