For the Anti-Xa 2-stage assay, for performing the method in compliance with new USP or EP guidances, the needs are summarized in the table below, for LMWH or UFH:
Anti-Xa 2-stage (# 221005) Volume of buffer (for 1 mL of reagent)   Buffer used  
Heparin measured LMWH UFH LMWH UFH
Sample     # AR005L (EP) # AR028K (USP) # AR030K (USP and EP)
R1 4mL 4mL # AR005L (USP and EP) # AR030K (USP and EP)
R2 4mL 4mL # AR005L (USP and EP) # AR030K (USP and EP)
R3 4mL   # AR029K (USP and EP)  


For the Anti-IIa 2-stage assay, for performing the assay in compliance with the new USP or EP guidelines, the needs are summarized in the table below:
Anti-Xa 2-stage (# 220005) Volume of buffer (for 1 mL of reagent)   Buffer used  
Heparin measured LMWH UFH LMWH UFH
Sample     # AR005L (EP) # AR028K (USP) # AR030K (USP and EP) or # AR031K (USP)
R1 4mL 4mL # AR005L (USP and EP) # AR030K (USP and EP) or # AR031K (USP)
R2 4mL 4mL # AR005L (USP and EP) # AR030K (USP and EP) or # AR031K (USP)
R3 4mL   # AR029K (USP and EP)  


Smart Buffers by Medicago available in pre-measured pouches for use with compendial tests.
For large volume industrial Heparin testing, in compliance with USP/EP guidances of anti-Xa and anti-IIa assay buffers:
Aniara SKU A12-0018 A12-0102 A12-0103 A12-0104 A12-0105
Product Name USP-EP Anti-FXa & Anti-FIIa Assay for UFH BUffer with PEG, pH 8.4 USP Anti-FXa & Anti-FIIa Assay for LMWH Buffer with PEG, pH 7.4 USP Anti-FXa & Anti-FIIa Assay for LMWH Buffer, pH 7.4 USP-EP Anti-FXa & Anti-FIIa Assay for LMWH Buffer, pH 8.4 USP-EP Anti-FXa & Anti-FIIa Assay for LMWH BUffer with BSA, pH 7.4
NaCI 0.175 M 0.150 M 0.150 M 0.175 M 0.150 M
Tris 0.050 M 0.050 M 0.050 M 0.05 M 0.050 M
EDTA 0.0075 M – – 0.0075 M –
Polyethylene glycol 6000 0.010% 0.10% – – –
Bovine serum albumin – – – – 1.0%
pH 8.4 7.4 7.4 8.4 7.4
Final volume 1 L 1 L 1 L 0.5 L 1 L
*PEG or BSA buffer can be used in USP test for LMWH.


Use charts below to determine the buffer needed for specific assay.
Product Name USP-EP Anti-FXa & Anti- FIIa Assay for UFH Buffer with PEG, pH 8.4 USP Anti-FXa & Anti-FIIa Assay for LMWH Buffer with PEG, pH 7.4 USP Anti-FXa & Anti-FIIa Assay for LMWH Buffer, pH 7.4 USP-EP Anti-FXa ∓ Anti- FIIa Assay for LMWH Buffer, pH 8.4 USP-EP Anti-FXa & Anti- FIIa Assay for LMWH Buffer with BSA, pH 7.4
USP Xa-UFH •        
USP IIa-UFH •        
USP Xa-LMWH   • • • •
USP IIa-LMWH   • • • •
USP Use: Dilution Buffer for Standards, Samples, AT, FXa, Thrombin, Blank Dilution Buffer* for AT, FXa, Thrombin Dilution Buffer for Standards, Samples, Blank Dilution Buffer for Substrate Dilution Buffer* for AT, FXa, Thrombin

Product Name USP-EP Anti-FXa & Anti- FIIa Assay for UFH Buffer with PEG, pH 8.4 USP Anti-FXa & Anti-FIIa Assay for LMWH Buffer with PEG, pH 7.4 USP Anti-FXa & Anti-FIIa Assay for LMWH Buffer, pH 7.4 USP-EP Anti-FXa ∓ Anti- FIIa Assay for LMWH Buffer, pH 8.4 USP-EP Anti-FXa & Anti- FIIa Assay for LMWH Buffer with BSA, pH 7.4
EP Xa-UFH •        
EP II-UFH •        
EP Xa-LMWH •     • •
EP IIa-LMWH       • •
EP Use: Dilution Buffer for Standards, Samples, AT, FXa, Thrombin, Blank     Dilution Buffer for Substrate Dilution Buffer for Standards, Samples, AT, FXa, Thrombin, Blank