Deep vein thrombosis / pulmonary embolism

Laboratory tests

• FBC
• Serum creatinine with eGFR
• D-dimerif neededLow or intermediate clinical probability on the Wells score; D-dimers are not measured if the clinical probability is high ^[2].
• PT, aPTT (if an anticoagulant is started)if needednon-French guidelineNICE (2020) has PT and aPTT measured, with FBC and kidney and liver function, as baseline tests at the start of any anticoagulant treatment of DVT or pulmonary embolism, without waiting for the results to treat ^[3]. SPLF (2019) does not list them in its pre-treatment tests, which include creatinine clearance and platelet count, but an abnormal PT enters the RIETE bleeding score that it uses to decide on outpatient management ^[2]. NICE does not detail the value of these two tests (committee opinion, ungraded) ^[3].

Laboratory tests

• FBC
• Serum electrolytes
• Serum creatinine with eGFR
• AST
• ALT
• GGT
• ALP
• Bilirubin
• Serum calciumif neededFirst unprovoked episode (looking for occult cancer): FBC and serum calcium ^[2].
• Serum albuminif neededFirst unprovoked episode (looking for occult cancer): FBC and serum calcium ^[2].
• PSA if man > 50 yearsif neededFirst unprovoked episode: update the recommended screening tests, unless done less than a year ago ^[2].
• Cervical smear or HPV test depending on ageif neededWoman, first unprovoked episode: update the recommended screening, unless done less than a year ago ^[2]. The HPV test replaces cytology from age 30, the smear remains the test from 25 to 30 ^[6].
• antiphospholipid syndrome tests (lupus anticoagulant, anticardiolipin antibodies, anti-beta2-GP1 antibodies)if neededFirst unprovoked episode of proximal DVT or PE before age 50, recurrent VTE, thrombosis at an unusual site, or DVT/PE associated with skin necrosis or a history of placental vascular disease (unexplained fetal death beyond 10 weeks of gestation, delivery before 34 weeks for eclampsia, severe pre-eclampsia or placental insufficiency, 3 consecutive miscarriages before 10 weeks) ^[2]. ESC considers these tests only before age 50 in the absence of an identifiable risk factor ^[7].
• inherited thrombophilia tests (protein C, protein S, antithrombin III, testing for factor V Leiden mutation and factor II (prothrombin) G20210A mutation)if neededSPLF (2019): first unprovoked episode of proximal DVT or PE before age 50 with a 1st-degree family history, unprovoked thrombosis at an unusual site, or recurrence before age 50 ^[2]. GFHT (2022): from the first spontaneous proximal episode, or one provoked by a minor (or hormonal) factor, before age 50, with no family history required ^[8]. In a specialised laboratory, between the 3rd and 6th month after the thrombosis ^[2].

• Diagnosis: complete bilateral venous duplex ultrasound of the lower limbs (no laboratory test to confirm or exclude superficial vein thrombosis).

Laboratory tests before anticoagulant treatment

• FBC (platelets)if neededSVT treated with fondaparinux or LMWH: platelet count before any treatment with heparin, LMWH or fondaparinux, or as early as possible after its start (grade 1+) ^[2].
• Serum creatinine with eGFR (Cockcroft–Gault clearance)if neededSVT treated with fondaparinux: no fondaparinux 2.5 mg if Cockcroft clearance is < 30 mL/min; between 20 and 30 mL/min, tinzaparin at prophylactic dose ^[2].