Interindividual variation in relationships between plasma heparin concentration and the results of five heparin assays

Putten, Janjaap van; Ruit, Marjo van de; Beunis, Marlene; Hemker, H.C.

doi:10.1016/0009-8981(82)90285-6

Cited by 28 publications

(16 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has earlier been shown that two-stage CS assays for heparin have better accuracy than clotting assays [28,29], Linear standard curves, which nearly coincide for UH and LMWH ( fig. 1) are other practical arguments in favour of this assay for monitoring hepa rin therapy.…”

Section: Discussionmentioning

confidence: 89%

See 1 more Smart Citation

Monitoring Therapy with LMW Heparin: A Comparison of Three Chromogenic Substrate Assays and the Heptest Clotting Assay

Abildgaard¹,

Norrheim²,

Larsen³

et al. 1990

Pathophysiol Haemos Thromb

View full text Add to dashboard Cite

Three LMW heparins (LMWH), one unfractionated heparin (UH), and international standards of LMWH and UH were compared in three chromogenic substrate (CS) assays and the ‘Heptest’ clotting assay. With a two-stage CS assay, linear standard curves were obtained in the 0.1–1.0 U/ml range, nearly coinciding for all preparations. With the one-stage CS assays, standard curves were curvilinear and similar for UH and the LMWH groups. In the Heptest assay, standard curves were linear for UH but not for LMWH. Mean recovery of LMWH, added to patients’ plasma samples was 70–98% for the four assays. Variation between individual recoveries was much greater with Heptest (coefficient of variation (CV) 35–44%) than with one-stage CS assays (CV 14–21 %) or two-stage CS assays (CV 7–8 %). For monitoring LMW heparin therapy, CS assays seem preferable to Heptest. The two-stage CS assay had superior accuracy, but the one-stage CS assays were easier to perform.

show abstract

Section: Discussionmentioning

confidence: 89%

“…The test result will then also depend on the plasma antithrom bin level. Unless antithrombin deficiency is pronounced, this aspect is usually not clini cally important [28],…”

Section: Discussionmentioning

confidence: 99%

Monitoring Therapy with LMW Heparin: A Comparison of Three Chromogenic Substrate Assays and the Heptest Clotting Assay

Abildgaard¹,

Norrheim²,

Larsen³

et al. 1990

Pathophysiol Haemos Thromb

View full text Add to dashboard Cite

show abstract

“…More important, the same amount of heparin activity produces very variable prolongation of the aPTT in different individuals [32][33][34]. Most important: the aPTT is insensitive to moderate inhibition of thrombin generation that already has an antithrombotic effect.…”

Section: On Measuring Heparins In Clinical Practicementioning

confidence: 99%

Conjectures and Refutations on the Mode of Action of Heparins

Béguin

Welzel²,

Dieri³

et al. 1999

Pathophysiol Haemos Thromb

View full text Add to dashboard Cite

Low-molecular-weight heparins (LMWHs), like unfractionated heparin (UFH), exert their action primarily by accelerating the interaction between antithrombin (AT) and thrombin. At the levels of aXa activity that are attained in human pharmacology, it does not cause significant (>15%) inhibition of the clotting system. The essential differences between LMWHs and UFH are: (a) LMWHs attain higher plasma concentrations after subcutaneous injection (high bioavailability), and (b) in contrast to LMWHs, UFH contains very large heparin molecules with a putative hemorrhagic action. The reputedly higher aXa activity of LMWH can be shown to be largely due to the absence of Ca²⁺ using the current laboratory methods to estimate this activity. Via this artifact the apparently high aXa activity of LMWHs is correlated but not related to their favorable pharmacokinetic properties. Consequently dosage guidelines for the use of different LMWHs cannot be based upon their aXa activity. Until better laboratory methods are available, clinical results are the only reliable guideline to heparin dosage.

show abstract

“…This assay allows an accurate reading within a rather broad range, in contrast to APTT, the reproducibility of which de creases with increasing clotting times [12,13]. Also the chromogenic assay is more specific for the hep arin level.…”

Section: L Standard Unfractionated Heparin (Sh)mentioning

confidence: 99%

New developments in the treatment of deep venous thrombosis

Janssen¹,

Nováková²,

Verbruggen³

et al. 1997

The Netherlands Journal of Medicine

View full text Add to dashboard Cite

An initial course of standard heparin (SH) or low-molecular-weight heparins (LMWH) is regarded as the treatment of choice for patients with deep venous thrombosis (DVT). LMWH have better bioavailability after subcutaneous administra tion, have a longer half-life, and show higher and more predictable anticoagulant activity. As a result they can be given subcutaneously and without laboratory control, using a dose that is determined by body weight. Because of these multiple advantages of LMWH they will replace SH in the future and subsequently home treatment with LMWH of selected patients seems feasible. The currently accepted approach is to start with SH or LMWH therapy combined with oral anticoagulant therapy (OAT) at the time of diagnosis. The course of SH or LMWH should continue for at least 5 days, provided that international normalized ratio (INR) is in the therapeutic range on 2 consecutive days. OAT should be continued for at least 3 months to prolong the prothrombin time to an INR of 2 -3 . When oral anticoagulants are either contraindicated or inconvenient, SH or LMWH can be used at the middosing interval. The role of anti-platelet treatment is not yet established 4 and should be compared with coumarin therapy in the future.

show abstract

Interindividual variation in relationships between plasma heparin concentration and the results of five heparin assays

Cited by 28 publications

References 3 publications

Monitoring Therapy with LMW Heparin: A Comparison of Three Chromogenic Substrate Assays and the Heptest Clotting Assay

Monitoring Therapy with LMW Heparin: A Comparison of Three Chromogenic Substrate Assays and the Heptest Clotting Assay

Conjectures and Refutations on the Mode of Action of Heparins

New developments in the treatment of deep venous thrombosis

Contact Info

Product

Resources

About