ELISAEnzyme linked immunosorbent assay (ELISA) is a highly sensitive immunological detection method widely used in biomedical research and clinical diagnosis. Despite its strong specificity, false negative results may still occur in practical operations, where the target substance is actually present in the sample but not detected. This not only affects the accuracy of experimental data, but may also lead to erroneous scientific or clinical judgments. Based on comprehensive analysis, the problem of false negatives mainly stems from the following three aspects.

Classification and analysis of influencing factors

1、 Sample factors

Window period impact: after infection2-3Insufficient antibody concentration within the week may lead to false negatives.

Improper sample handling:

Repeated freezing and thawing damage the antibody structure;

Hemolysis, hyperlipidemia, or bacterial contamination interference detection;

Use heparin/EDTAWait for anticoagulant to inhibit enzyme activity.

IIReagent related factors

The quality and applicability of reagents are prerequisites for ensuring detection accuracy.

1、Reagent quality issues: use without approval number, expiration or improper storage (such as4Reagents refrigerated at ℃ may cause a decrease in sensitivity.

2、Reagent cross reactivity: Some mutants (such asHBVofSGenetic mutations may alter antigen epitopes, leading to ineffective recognition of antibodies in commercial test kits and resulting in missed detections.

3、Drug interference: high titer hepatitis B immunoglobulin in patients（HBIG）Can be withHBsAgForming a complex that hinders its detection.

3、 Operational related factors

A standardized operating procedure is the key to obtaining reliable results.

1、Sample addition problem: Insufficient sample amount, long sample addition time (especially for weakly positive samples), or inaccurate pipette can all lead to low signal.

2、Incubation conditions: Incubation temperature (usually37If the temperature and time are not strictly controlled, it will affect the efficiency of antigen antibody binding.

3、Washing problem: Washing the board too many times or with too much force may result in the loss of bound immune complexes.

4、Color development and interpretation: If the color development time is too short, low titer samples may not have enough time to develop color; Not using dual wavelength readings may increase background interference, leading to weak positives being misjudged as negatives .

4、 Endogenous interference

Non specific substances such as rheumatoid factor and complement bind to antibodies, leading to false positives or false negatives;

Immunosuppressive patients (such as AIDS) have insufficient antibody production.

5、 Other reasons

Gene mutations affect antibody binding sites;

Limitations of detection methods (such asELISAInsufficient sensitivity

suggestion

to avoidELISAFalse negative, it is recommended to take the following measures:

1、For strongly positive suspicious samples, perform gradient dilution before testing to exclude hook effect.

2、Prioritize the use of two-step assay kits as they are less susceptible to hook effects.

3、Strictly follow the instructions to ensure standardized reagent balance, incubation time, and plate washing procedures.

4、For results that are critical or negative but highly suspected clinically, other testing methods should be combined (such as...)PCR）Conduct a review.

By understanding these factors and taking corresponding preventive measures, it is possible to reduceELISAFalse negative results in the experiment.