Allen's test


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Related to Allen's test: Adson's test, Homans sign, Buerger's test

Allen's test

 [al´enz]
a test for occlusion of radial or ulnar arteries: the patient makes a tight fist so as to express the blood from the skin of the palm and fingers; the examiner makes digital compression on either the radial or ulnar artery. Failure of blood to return to the palm and fingers when the hand is opened indicates obstruction of the blood flow in the artery that has not been compressed. Either this test or a doppler ultrasound examination should always be performed prior to insertion of a radial artery line.

Allen's test

[Edgar Van Nuys Allen, American physician, 1893-1986],
a test for the patency of the radial artery after insertion of an indwelling monitoring catheter. The patient's hand is formed into a fist while the nurse compresses the ulnar artery. Compression continues while the fist is opened. If blood perfusion through the radial artery is adequate, the hand should flush and resume its normal pinkish coloration. The accuracy and utility of the Allen's test has been questioned in the research literature.
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Allen's test

Allen's test

A clinical test used to evaluate ulnar-artery patency before radial-artery cannulation or radial-artery harvesting for coronary-artery bypass grafting.
Method Simultaneous compression of both the radial and ulnar arteries, followed by exsanguination of blood from the palm by repeated clenching and unclenching of the fist. The pressure over the ulnar artery is then released while maintaining pressure over the radial artery. A 5–6 second delay in flushing of the palm suggests abnormal ulnar-artery patency.

Allen's test

Rehabilitation medicine A test used to determine patency of the ulnar or radial artery; the hand is clenched to force blood out; if the blood does not flow back into the hand rapidly, one or more arteries are stenosed or occluded–eg, due to throacic outlet syndrome

test

trial/experiment assisting diagnosis
  • Allen's test test of arterial occlusion in the foot, i.e. leg elevation (until plantar skin blanches and Doppler sound at dorsalis pedis [DP] pulse is lost) followed by compression of DP pulse (by clinician's thumb) and lowering of leg to dependency; if posterior tibial artery flow is adequate the foot rapidly resumes its normal colour; test is repeated at posterior tibial pulse, to test patency of DP

  • anterior drawer test; ADT; Lachman's test test of stability/integrity of lateral collateral ligaments of ankle joint, i.e. flex knee to >45° (to relax posterior muscle group), stabilize lower tibia (with one hand) whilst grasping posterior aspect of patient's heel (with the other); calcaneum is pulled forward as a simultaneous retrograde force is applied to lower tibia; positive ADT = > 4mm anterior displacement of foot relative to tibia together with positive 'suction sign'

  • Buerger's test test of arterial status of lower limb, i.e. patient reclines supine on couch; leg is elevated (from hip) for 1 minute (whilst patient alternately dorsi- and plantarflexes ankle joint, to drain venous circulation); limb is lowered to dependency or patient stands up (foot shows brief hyperaemia before returning to normal skin colour); time (in seconds) for normal colour return is noted; >20 seconds = inadequate arterial supply; >40 seconds = severe limb ischaemia; note: clinician should note whether cyanosis (rather than brief hyperaemia) occurs on dependency, and duration of cyanosis; persistent dusky red/purple coloration in dependent limb that appears to resolve to normal skin tone on raising limb to horizontal indicates severe arterial compromise

  • Clarke's test diagnostic test of chondromalcia patellae; with the patient supine and the affected knee fully extended, the clinician applies gentle pressure to the patella whilst the patient attempts to contract the quadriceps muscle group; the test is positive if severe patellar pain occurs

  • Coombs test test to predict donor and receiver blood compatibility, i.e. assay for presence/absence of specific antibodies on donor erythrocytes

  • coordination tests tests of cerebellar coordination of lower-limb motor function, i.e. heel-shin test; fingertip test

  • fingertip test test of cerebellar function, i.e. patient repeatedly attempts to place his/her fingertip on tip of assessor's moving finger; alternatively, patient attempts to put tip of his/her index finger alternately on his/her nose then on assessor's moving finger

  • glass test test for meningitis, i.e. test is positive when there is no blanching of a pruritic rash when it is pressed with a glass

  • glucose tolerance test; GTT diagnostic test of diabetes mellitus, and assessment of patients with fasting blood glucose levels just above normal range (i.e. 5.6-6.7 mmol/L), i.e. 75mg glucose is given (as a drink) after starving for 12-14 hours; its rate of blood clearance is monitored over the next 3 hours; in normal patients, there is an immediate and sharp rise in blood glucose which falls during subsequent 2 hours to normal glycaemic levels (i.e. 2.9-5.9 mmol/L); in diabetes/insulin resistance cases, blood glucose levels rise initially to a higher level and do not return to normal range within 2 hours

  • Heaf test test of immunity to tubercle bacillus (tuberculosis [TB]), i.e. subdermal injection of attenuated tuberculin toxin

  • heel-shin test test of cerebellar function, i.e. patient repeatedly places one heel on anterior aspect of other shin and slides heel down to dorsum of foot; inability to perform this test indicates cerebellar dysfunction and other conditions characterized by loss of motor coordination

  • interdigital test reduced blunt/sharp discrimination, paraesthesia, hyper-/hypoaesthesia of interdigital skin at toe cleft affected by neuritis/Morton's neuroma

  • Jack's test passive dorsiflexion of hallux at first metatarsophalangeal joint in weight-bearing foot

  • Kelikian push-up test intraoperative check of adequate surgical correction of lesser-toe deformity, i.e. elevation of head of relevant metatarsal with thumb pressure

  • Lachman's test see test, anterior drawer

  • Mantoux test, tuberculin test screening test for exposure to tuberculosis (TB); administration of an intradermal dose of tuberculosis antigen (tuberculin) to the skin of the forearm; a localised, small, firm inflammatory skin reaction developing within 2 days shows positive exposure to tuberculosis

  • Mulder's test diagnostic test for Morton's neuroma, i.e. simultaneous lateral compression across metatarsal heads + thumb pressure at affected plantar web space in a foot with symptoms of plantar digital neuritis (Morton's neuroma); positive result (i.e. induction of characteristic symptoms of a nerve entrapment pain, and examiner's awareness of a fluid thrill [or click] within the palpated tissue) indicates neuritis or neuroma

  • Nobel's test test for iliotibial band (ITB) syndrome, i.e. palpation of lateral tibial condyle causes ITB pain

  • Ober's test test for iliotibial band (ITB) syndrome, i.e. excessive tightness/tension on palpation of the ITB

  • patch test; skin test test of hypersensitivity, i.e. application of a range of potential sensitizing agents to skin (e.g. back, ulnar aspect of arm); degree of inflammatory reaction (provoked by test agents) is compared with a control (innocuous substance) and 'read'/assessed after 48-96 hours

  • pole test test to estimate foot systolic pressures in limbs with arterial calcification, i.e. with patient supine, leg is elevated until Doppler foot pulses cease, and elevation height (in cm) from apex of hallux to bench is noted and multiplied by 7.35

  • Romberg's test test comparing amount of body sway of an erect patient with eyes closed and eyes open; test is positive if patient shows loss of balance/increased tendency to sway when standing with eyes closed

  • screening test any test that categorizes by predetermined characteristic/property

  • single-leg raise test; tiptoe test test of tendo Achilles (TA), tibialis posterior and peroneal integrity/function, i.e. patient stands on one leg and weight-bears on tiptoe; patient with TA damage will not be able to rise normally to tiptoe on affected side; with TA rupture, patient will not be able to rise up on to tiptoe on the affected limb at all; heel pain during single-leg raise is indicative of Sever's disease see sever's

  • skin test see test, patch

  • talar tilt test test of integrity of lateral collateral ligament of the ankle, calcaneofibular ligament and tibialis posterior tendon, i.e. with the ankle joint at neutral (0° dorsiflexion) the calcaneum is passively inverted by the examiner; if the lateral collateral ligament is damaged (e.g. anterior talofibular ligament rupture) excessive talar excursion occurs; tissue dimpling inferior to the lateral malleolus indicates rupture of the calcaneofibular ligament; greater than expected talar eversion and flattening of the medial longitudinal arch indicate tibialis dysfunction

  • Thompson's test test of Achilles tendon function, i.e. with the patient lying prone, the posterior calf muscle group is squeezed, causing ankle joint plantarflexion; the foot does not plantarflex in total Achilles tendon rupture

  • thumb roll test test for 'runner's knee', i.e. the knee is flexed by 30-40° and the examiner's thumb rolled across the medial aspect of the patella, causing a painful 'snap' or 'click', and detection of a fibrous ridge/'shelf' at anterior knee compartment

  • Trendelenburg's test test of the quality of venous filling time, and quality of venous drainage in the leg, i.e. carried out as Buerger's test, but the time (in seconds) taken for the dorsal foot veins to refill and the direction of blood flow into the dorsal foot veins is noted; refill from proximal to distal indicates venous backflow and vein valve incompetence

  • Tuberculin test see Mantoux test

  • urea breath test test to detect Helicobacter pylori gastritis, or confirm its eradication, i.e. by analysis of exhaled breath

  • Valsalva's test test to detect autonomic neuropathy, i.e. the patient exhales into an empty plastic syringe (the other end of which is connected to a manometer to be maintained at 40mmHg) for 10 seconds, and changes in heart rate are noted (i.e. maximum expiratory heart rate and minimum heart rate after test cessation), and compared as a ratio; ratio of <1:10 indicates autonomic neuropathy (normal = >1:21)

  • vertical stress test test of plantar plate rupture, i.e. application of vertical stress to metatarsal head; translocation (i.e. > 2mm dorsal elevation) of base of toe in relation to dorsum of metatarsal head indicates plantar plate rupture

  • vibration test test of peripheral sensory function (assessing pacinian corpuscle function), i.e. application of vibration stimuli (from activated 128Hz tuning fork or neuraesthesiometer) to bony prominences (e.g. medial aspect of first metatarsophalangeal joint, lateral aspect of fifth metatarsal styloid process, medial and lateral malleoli, tibial tuberosity); vibrational awareness is reduced in the elderly and may be lost in diabetic distal sensory neuropathy, correlating with reduced pain awareness

References in periodicals archive ?
Evaluation of the ulnopalmar arterial arches with pulse oximetry and plethysmography: comparison with the Allen's test in 1010 patients.
If Allen's test is negative for both hands and radial artery is not accessible, then the brachial artery may be used.