Q: Which type of biological samples (serum, plasma, saliva..etc) can I test in Calbiotech kits?
A: The package insert of each kit specify the type of the biological sample that can be tested with.
Q: The OD readings of the standards or the controls I obtained, don't match the ones in the package insert?
A: The OD readings mentioned in the package insert are just an example. It doesn't reflect the actual readings, each laboratory is encouraged to establish its own criteria for test interpretation based on sample populations encountered.
Q: How do I determine my unknowns?
A: Use data analysis software, like GraphPad Prism, SoftMax Pro or other commercially available products.
Q: What curve fitting method should I use?
A: Point-to Point Method, 4 parameter


Weak or no signal Enzyme conjugate was not added.
Add Enzyme conjugate.
Substrate Reagent was not added.
Add Substrate.
Very low incubation temperature or agitation.
Control your room (lab) temperature to bring it within the recommended range (Refer to the Package Insert). Set your plate shaker to 600rpm.
High background across the plate. Standard curve is saturated.
Wrong conjugate dilution used.
Dilute the conjugate at the recommended dilution.
The assay was incubated for too long in one or all steps.
Strictly follow the assay incubation time in all steps according to the procedure.
The substrate is contaminated (not fresh).
Check the color of the substrate - it should be colorless.
High incubation temperature.
Control your room (lab) temperature to bring it within the recommended range (Refer to the Package Insert).
Positive signal (high background) in negative controls or standard wells.
Contaminated Pipette tips.
Use clean pipette tips and change tips for every sample and/or standard.
Cross contamination has occurred between wells.
Carefully wash wells. The wash step is very critical.
High CV across the plate (high variation in samples / standards).
Pipetting problem. When using: Single Channel Pipette: Check tips for bubbles between replicates. Multichannel Pipette: Calibrate the pipette. Check tips for bubbles before dispensing.
Non-Uniform Washing. All the wells should be uniformly washed. Check your washing system and/or method.
Non-homogeneous reagents (samples/standards)
Vortex samples to ensure homogeneity before pipetting.
Sample Readings are out of the assay dynamic range.
Sample contains undetectable analysis level, i.e. below assay limit of detection (LOD).
If samples fall below the LOD, contact us: support@calbiotech.com
Sample contains high analyte level: i.e. above assay highest standard point.
Samples should be diluted and re-assayed.